randomQuestions

Algorithm that calculate multiplication operation using the addition operation

  public static void main(String[] args) {
        
        int multiplier = 5;
        int multiplicand = 3;
        int sum = 0;
            
        for ( int i =1; i <= multiplier; i++){
        
            sum += multiplicand;
            
        
        }
     
        System.out.println(sum);
    }

Algorithm that calculate divison operation using extraction operation.

   public static void main(String[] args) {
   
        int dividing = 10;
        int dividing2 = 2;
        int counter = 0; 
        
        while ( dividing > 0){
        
           dividing -= dividing2;
           counter++;
        
        }
        System.out.println(counter);
        
    }

Algorithm that checks whether the sum of the three digits of a 3-digit number is equal to itself

 public static void main(String[] args) {
       
        for ( int number = 100; number <1000; number++ ){
        
        int keep = number;
    
            int hundredsDigit = keep/100;
            keep = number - hundredsDigit*100; 
            
            int tensDigit = keep/10;
            keep = keep - tensDigit*10;
            
            int onesDigit = keep/1;
            keep = keep - onesDigit*1 ; 
            
        double hundreds = Math.pow(hundredsDigit,3);
        double tens = Math.pow(tensDigit, 3);
        double ones = Math.pow(onesDigit, 3);
        
        double sum = hundreds + tens + ones;
        
      
        if ( sum == number )
            System.out.println(number);
        
        }
    }

Algorithm that finding perfect square numbers between of 10, 1000

public static void main(String[] args) {
        
        for ( int i = 10 ; i <= 1000; i++){
        
            for ( int j = 4; j < 100; j++){
            
                int sqr = j*j;
                
                if ( sqr == i){
                
                    System.out.println(i);
                    
                }
                
            }
        
        }
     
    }

Algorithm to find whether the entered number is a power of 5

public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        int number = s.nextInt();
        
        if ( number % 5 == 0){
        
            System.out.println(number + " is power of 5");
        }
        else {
        
            System.out.println(number + " isn't power of 5");
        }
        
     
    }

Algorithm that check friendly number to entered two numbers.

public static void main(String[] args) {
        
        // friendly number = If two numbers are equal to the sum of their divisors excluding each other, these numbers are called friend numbers.
        
        Scanner s = new Scanner (System.in);
        
        int x = s.nextInt() , y = s.nextInt();
        int sumX =0, sumY =0;
     
        for ( int i = 1; i < x; i++){
        
            if ( x % i == 0){
        
                sumX += i;
         }
   
        }
        
        for ( int i = 1; i < y; i++){
        
            if ( y % i == 0){
            
                sumY += i;
            }
        }
        
        if ( sumX == y && sumY == x){
        
            System.out.println("They're friendly number.");
        }
        else {
        
            System.out.println("They aren't friendly number.");
        }
        
        
        
    }

Algortihm that check abundant number or deficient number entered from keyboard.

public static void main(String[] args) {
        
        // abundant number = the sum of its multipliers is bigger than itself
        // deficient number = the sum of its multipliers is less than itself
        Scanner s = new Scanner (System.in);
        
        int sum =0; 
        int number = s.nextInt();
        
        for ( int i =1 ; i < number; i++){
        
            if( number % i == 0){
                
                sum += i;
     
            } 
        }
     
        if ( sum > number){
        
            System.out.println(number + " is a abundant number.");
        }
        else if ( sum < number){
            
            System.out.println(number + " is a deficient number.");
        }
        else {
            System.out.println(number +"is a normal number.");
        }
        
    }

Algorithm that 6 steps for finding random number of between 1 - 63 integer numbers.

 public static void main(String[] args) {
        
        Scanner s = new Scanner ( System.in);
        
        int number = s.nextInt();
 
        int floor = 1 , ceiling = 63;
        int keep; 
        
        
         if ( number > 62 || number < 2 ){
        
            System.out.println("Please select number between of 1 and 63");
            System.exit(0);
        }
        
        for ( int i =1; i <= 6; i++){
        
            keep =(ceiling + floor)/2;
            
            System.out.println("keep =" + keep);
           
        
            if ( keep == number ){
            
                System.out.println("I finded number = " + number);
                System.exit(0);
            }
            else if ( number > keep ){
            
                floor = keep;
                System.out.println("Bigger than " + keep);
            }
            else {
            
                ceiling = keep;
                System.out.println("Less than");
            }
            
        }
        
     
    }

Algrotihm that decimal convert to binary number.

 public static void main(String[] args) {
        
        Scanner s = new Scanner(System.in);
        
        int number = s.nextInt();
        int keep = number;
        
        int counter = 0 ;
        
        while ( keep > 0 ){
            keep /= 2;
            counter++;
        }
        
        int binary [] = new int [counter];
        
        
        for ( int i = counter-1; i >= 0; i--){
        
        keep = number % 2;
        number /= 2;
        
        
         if ( keep == 0){
            
            binary[i] = 0;
            
         }
        
         else {
            
            binary[i] = 1;
             
         }
            
        }
    
        for ( int i =0 ; i < binary.length; i++){
        
            System.out.print(binary[i]);
        }
        
    }

Algortihm that binary number convert to decimal number

public static void main(String[] args) {
     
        Scanner s = new Scanner ( System.in);
        
        double counter =0;
        String binary = s.next();
        double pwr;
        int sum =0;
        
        for ( int i = binary.length()-1 ; i >= 0; i--){
        
            char no = binary.charAt(i);
            
            if ( no == '1' ){
            
                pwr = Math.pow(2, counter);
                sum += pwr;
            
            }
            else {
            
            }
            counter++;
        
        }
        System.out.println(sum);
        
    }

Algorithm that finding t time of an airplane accelerates smoothly for 15 minutes and its speed becomes 480 km/h. Then at constant speed for 20 min. It goes and slows down smoothly for 15 minutes, and its speed becomes zero.

public static void main(String[] args) {
     
        Scanner s = new Scanner ( System.in );
        
        int t = s.nextInt();
        int plane = 0;
        int list[] = new int [51];
        list[0] = 0;
                
        for (int i = 1 ; i <= 15; i++){
        
            plane += 32;
            list[i] = plane;
        }
        for ( int i = 16; i <= 35; i++){
            plane += 0;
            list[i] = plane;
        }
        
        for ( int i= 36; i < 50; i++){
        
            plane -= 32;
            list[i] = plane;
        }
        
        
        if ( t < 0 || t > 50){
        
            System.out.println("Plane is standing");
        
        }
        else {
            
            System.out.println("Plane's speed = " + list[t]);
        }
        
    }

Algorithm that check number original number or not of 4 digit numbers

public static void main(String[] args) {
     
        // original number = square of sum of its digits first two digits and last two digits equals its number
        
       
        int firstDigits , lastDigits, keep , sum;
        double pwr;
       
        
        for ( int i =1000 ; i <10000; i++){
 
        keep = i ;  
        
        firstDigits = i /100;
        
        keep -= (firstDigits*100);
        
        lastDigits = keep;
        
        sum = firstDigits + lastDigits;
        
        pwr = Math.pow(sum , 2);
        
        
            if ( pwr == i){
        
                System.out.println(i);
            }
        
        }

    }

Algrorithm that check smith number or not of 4 digit numbers

public static void main(String[] args) {
        
        // smith number = If the sum of the digits of a non-prime integer greater than 1 is equal to the sum of the digits of all prime numbers in that spelling when the number is written by factoring the prime.
        
        int thousands , hundreds, tens, ones;
        int keep ;
        int sum = 0 , sum2 = 0;
        
        for ( int i = 1000; i < 10000; i++){
        
            keep = i;
            
            thousands = i / 1000;
            i -= thousands*1000;
            
            hundreds =  i / 100;
            i -= hundreds*100;
            
            tens = i / 10;
            i -= tens*10;
            
            ones = i/1;
            
            sum += (thousands + hundreds + tens + ones);
           
            
            i = keep;
            
         
           for( int j = 2 ; j < i ; ){
            
                if ( keep % j == 0){
                
                sum2 += j;
                keep /= j;
    
                }
                else {
                    
                    j++;
                    
                }
              
            }
            
             if ( sum == sum2){
                System.out.println(i);
        
            }
             sum = 0;
             sum2 = 0;
    
            }
   
        }

Algorithm that finding biggest of number's digits.

 public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        int number = s.nextInt();
        
        System.out.println("Biggest digit of number = " + biggest(number));
    
    }
    
    public static int biggest ( int x){
    
    int digit = 0;
    int sum = 0;
    int keep = x;
    
    
        while ( x > 0){
        
         digit++;
         x /= 10;
    }
    
         x = keep;
    
    int list [] = new int [digit];
    
    int big = list[0];
    
        for ( int i =0 ; i < digit; i++){
    
            list[i] = x % 10;
    
            x /= 10;
            
            if ( big < list[i]){
                
                big = list[i];
                
            }
       
    }
    
    return big;
    
    }

Algorithm that degree convert to radian and grad.

// 180 degree = pi radyan = 200grad
    
    public static void main(String[] args) {
     
        Scanner s = new Scanner (System.in);
        
        double degree = s.nextInt();
        
        System.out.println(degree + " degree = " +convert (degree)[0] + " radian = " + convert(degree)[1] + " grad" );
    }
    
    public static double[] convert (double x){
    
        double radian = x / 180;
        double grad = (10 * x) / 9;
        
        double [] list = {radian, grad};
        
        return list;
        
    }

Algorithm that calculate series of 1+ x / 1! + x^2 / 2! + x^3 / 3! ... n and x entering from keyboard

public static void main(String[] args) {
        
        Scanner s = new Scanner ( System.in);
        
        System.out.println("Please enter the x value");
        
        double number1 = s.nextInt();
        
        System.out.println("Please enter the n value");
        
        double number2 = s.nextInt();
        
        System.out.println( calculate( number1 , number2 ));
    }
    
    public static double calculate ( double x , double n){
    
    double factorial = 1 ;
    double sum = 1;
    double pwr, keep;
    
    
    for ( int i = 1; i <= n ; i++){
    
        pwr = Math.pow( x , i);
        
        for ( int f = 1; f <= i; f++){
        
        factorial *= f;
        
        }
        
    keep = pwr / factorial;  
    sum += keep;
        
    factorial = 1 ;    
    
    
    }
    
    return sum;
    
    }

Algorithm that calculate series of 1-1 / 3+1 / 5-1 / 7+1 / 9-1 / .... / n +- 1 n enter from keyboard

public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        System.out.println("Please enter the n value");
        
        int number = s.nextInt();
        
        if ( number % 2 == 0){
        
            System.out.println("Please enter the odd number. ");
            System.exit(1);
        }
        
        System.out.println( calculate (number));
     
    }
    
    public static double calculate ( int x){
    
    double sum =0 ;
    
    for ( int i = 1; i <= x; i += 4){
    
        sum += (i -1);
    
    }
    for ( int i = 3; i <= x; i += 4){
    
        sum += (i+1);
    } 
    
    
    return sum;
    } 

Algorithm that calculate series of 1 - x^2 / 2! + x^4 / 4! - x^6 / 6! + x^8 / 8! / ... +- x^n / n! n enter form keyboard

   //              this series calcutaing of cos(x)

 public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        System.out.println("Please enter x value");
        double number = s.nextDouble();
        System.out.println("Please enter n value");
        double number2 = s.nextDouble();
        
        System.out.println( calculate (number , number2));
    }
    
    public static double calculate ( double x, double n){
    
    double sum = 1; 
    double factorial = 1;
    double pwr, keep;
    
    for ( int i = 2; i <= n; i += 4 ){
    
        pwr = Math.pow( x , i);
        
        for ( int f = 1; f <= n; f++){
        
            factorial *= f;
        }
        
        keep = pwr/factorial;
        factorial =1;
        
    sum -= keep;
    
    
    }
    
    for ( int i = 4; i <= n; i += 4){
    
        pwr = Math.pow( x, i );
        
        for ( int f= 1; f <= n; f++){
        
            factorial *= f;
        
        }
        
        keep = pwr/factorial;
        factorial =1; 
        
        sum += keep;
    
    }
    
    return sum;

Algorithm that calclate ∑ (1/i! + i/ (n-i)!. n enter from keyboard.

public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        double n = s.nextDouble();
        double sum =0; 
        double keep;
        double factorial =1 ;
        double factorial2 = 1;
        
        for ( int i = 1; i <= n; i++){
        
         for ( int f = 1; f <= i ; f++){
         
             factorial *= f;
         }
         for ( int f = 1; f < (n-i); f++){
         
             factorial2 *= f;
         }
         
         keep = (1/factorial) + ( i / factorial2 );
         sum += keep;
         factorial =1;
         factorial2 = 1;
        
        
        }
        System.out.println(sum);
  
    }

Algorithm that writing backwards of a word.

    public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
     
        String word = s.next();
        
        String turn = writeBackwards(word);
        System.out.println( turn);
    }
    
    public static String writeBackwards ( String x){
    
    String y = "" ;

    for ( int i =x.length()-1 ; i >= 0; i--){
    
        y += x.charAt(i);
        
    }
    
    return y;
    
    }

There is an array with N elements. Algorithm that places the numbers entered from the keyboard into the array, one from the beginning and one from the end.

 public static void main(String[] args) {
     
        Scanner s = new Scanner (System.in);
        System.out.println("Please enter the array's length");
        int x = s.nextInt();
        String [] list = new String[x];
        int lng = list.length;
       
    for ( int i = 0 , j = list.length-1; i < lng/2  ; i++, j--){
    
        list[i] = s.next();
        list[j] = s.next();
     
    }
    
    if ( lng % 2 == 1){
    
        System.out.println("Please enter middle and last value");
        list[lng/2] = s.next();
    
    }
    
    for ( int i =0; i < list.length; i++){
    
        System.out.print(list[i] + " ");
    }
        
    }

Algorithm that gives the following output

/*
    computer
    omputerc
    mputerco
    .
    .
    .
    computer
*/

    public static void main(String[] args) {
        
        String word = "computer";
        
        char c [] = convert(word);
        
        swiftAndWrite(c);
        
    }
        
        public static void swiftAndWrite(char c[]){
            
        for ( int i =0 ; i < c.length;i++){
    
              System.out.print(c[i] + " ");
        
        }
        System.out.println(" ");
            
            char keep = c[0];
        
        for ( int j =0 ; j < c.length; j++){ 
           
           keep = c[0];
           
        for ( int i = 0; i < c.length-1; i++){
            
           c[i] = c[i+1];
           
       }
        
       c[c.length-1] = keep;
       
        for ( int i =0 ; i < c.length; i++){
            
            System.out.print(c[i] + " ");
        }
        
       System.out.println("");
     
       }

    }
            

    public static char[] convert (String x){
    
    char c [] = new char [x.length()];
    
    for ( int i =0 ; i < x.length(); i++){
    
    c[i] = x.charAt(i);
    
    }
    return c;

    }

Algotihm that sorts an int array from largest to smallest.

public static int[] input(int x[]){
    
        Scanner s = new Scanner (System.in);
        
        for ( int i = 0; i < x.length; i++){
        
        x[i] = s.nextInt();
        
        }
        toSort(x);
        return x;
        
    }
    
    
    public static void toSort(int x[]){
        
        int keep; 
        
        for ( int i =0 ; i < x.length;i++){
        
            for ( int j = i+1; j < x.length; j++){
                
                if ( x[j] > x[i]){
                
                keep = x[i];
                x[i] = x[j];
                x[j] = keep;
                
                }
                
            }
        
        }
        output(x);
        
    } 
    
    
    public static void output (int x[]){
    
        for ( int i = 0; i < x.length; i++){
        
            System.out.print(x[i] + " ");
        }
    }
    
    
    public static void main(String[] args) {
        
        int [] list = new int[10];
        list = input(list);
    
    }

Algortihm that sum of two binary number

public static double[] convertDecimal ( String x, String y){
   
   int sumX = 0, sumY = 0;
   double decimal[] = new double[2]; 
    
    for ( int i =0, j = x.length()-1; i < x.length(); i++, j--){
    
        if ( x.charAt(i) == '1' ){
        
            sumX += Math.pow(2 , j);
            
        }
        
    }
    for ( int i =0 , j = y.length()-1; i < y.length(); i++, j--){
    
        if ( y.charAt(i) == '1'){
            
            sumY += Math.pow(2 , j);
        }
    }
    
    decimal[0] = sumX;
    decimal[1] = sumY;
    
    convertBinary(sumX+sumY);
    
    return decimal;
    }
    
    public static void convertBinary(int x){
    
    int counter = 0;
    int keep = x;
        
    while ( keep > 0 ){
    
        keep /= 2;
        counter++;
    }
    
    char bnry [] = new char [counter];
    keep = x;
    
    for ( int i =0; i < bnry.length; i++){
    
        keep = x % 2;
        x /= 2;
        
        if ( keep == 0 ){
        
            bnry[i] = '0';
        }
        else {
            bnry[i] = '1';
        }
    }
    
    output(bnry);
    
    }
    
    public static void output( char x[]){
    
    for ( int i =x.length-1; i >=0; i--){
    
        System.out.print(x[i] + " ");
    
    }
    }

    public static void main(String[] args) {
        
        String twentyThree = "10111";
        String nine = "1001";
        
        convertDecimal(twentyThree , nine);
    }

Algorithm that shifts it back to the beginning by removing the ones other than the first written number of the repeated numbers in a 7-element number array with the element values given.

public static void main(String[] args) {
        
        int list [] = {10 , 20, 30, 40 , 30 , 20 , 50};
        
        swift(list);
        
    }

    public static int[] swift ( int x[] ){
    
    int keep , counter=0;
        
    for ( int i = 0; i < x.length; i++){
        
        for ( int j = i+1; j < x.length; j++){
      
            
            if ( x[i] == x[j]){
                
                keep = x[j];
                        
                for (int s = j; s >counter; s--){
   
                    x[s] = x[s-1];
                }
                
                x[counter] = keep;
                counter++;
            }
        }
    }
    
    output(x);
    
    return x;
    }
    
    public static void output ( int x[]){
    
        for ( int i =0; i < x.length; i++ ){
        
            System.out.println(x[i]);
        }
    
    }
    

Algorithm that finding how much one digit, how much two digit, how much three digit of number array

public static void main(String[] args) {
        
        int list [] = { 10 , 100, 1, 200, 20};
        
        find(list);
        
    }
    
    public static int [] find ( int x[]){
        
    int counter =0, keep;  
    int digits [] = new int [x.length];
        for ( int i = 0; i < x.length; i++){
            
            keep = x[i];
            
            while ( x[i] > 0){
            
            x[i] /= 10;
            counter++;
            
            }
            
        digits[i] = counter;
        counter = 0;
        x[i] = keep;
        }
        output(digits);
        return digits;
    }
    public static void output (int x[]){
    
        for ( int i =0; i < x.length; i++){
        
            System.out.println(" Digit of element " + (i+1) + " = " + x[i] );
        }
    
    }

Half of the sum of the 1st and 2nd elements of a 10-element array is the first element of another array, and half of the sum of the 3rd and 4th elements is the 2nd element.

public static void main(String[] args) {
        
        int list [] = new int [10];

        elementsOfList(list);
        
    }
    
    public static int[] elementsOfList (int x[]){
    
        Scanner s = new Scanner(System.in);
        
        for ( int i =0; i < x.length; i++ ){
        
            x[i] = s.nextInt();
        }
        
        sumAndAssign(x);
        
        return x;
    }
    
    public static void sumAndAssign ( int x[]){
        
        int sum =0;
        int lastArray [] = new int[x.length/2];
    
    for ( int i =0 , j = 1, c =0;  i < x.length; i += 2, j +=2, c++ ){
        
        sum += (x[i] + x[j])/2;
        
        lastArray[c] = sum;
        
        sum = 0;
    }
        
        output(lastArray);
    }
    
    public static void output ( int x[]){
    
    for ( int i =0; i < x.length; i++){
        
            System.out.println(x[i]);
        }
    
    }

Algorithm that gives the transpose of a square matrix of type [2x2].

 public static void main(String[] args) {
        
        String list[][] = { {"Emirhan" , "Cakil"}, {"Computer" , "Science"} };
        
        output(list);
        
    }
    
    public static String[][] output (String x[][]){
    
        for ( int i =0; i < x.length; i++){
        
            for ( int j =0; j < x[0].length; j++){
            
                System.out.print(x[j][i] + " ");
            
            }
            System.out.println("");
        }
        
        return x;
    }

Algorithm that sum of two matrix

public static void main(String[] args) {
  
    int matrix1 [][] = {{1,2,3},{4,5,6},{7,8,9}};
    int matrix2 [][] = {{1,2,3},{4,5,6},{7,8,9}};

    sumOfMatrixs(matrix1, matrix2);
    
    }
    
    public static int[][] sumOfMatrixs ( int x[][] , int y[][]){
    
        int sums [][] = new int[3][3];
        
        for ( int i =0; i < x.length; i++){
        
            for (int j =0; j < x[0].length; j++){
            
                sums[i][j] = (x[i][j] + y[i][j]); 
            }
        }
        output(sums);
        
        return sums;
    
    }
    
    public static void output ( int x [][] ){
    
        for (int i =0; i < x.length; i++){
        
            for ( int j =0; j< x[0].length; j++){
                
                System.out.print(x[i][j] + " ");
            
            }
            System.out.println("");
        }
    
    }

Algorithm that convert two dimensional array to one dimensional array

public static void main(String[] args) {
        
        int matrix[][] = {{1,2,3},{4,5,6}};
        
        convert(matrix);
    }
    
    public static int[] convert(int x [][]){
    
        int lng = (x.length * x[0].length);
        
        int counter =0;
        
        int single[] = new int [lng];
    
        for ( int i =0; i < x.length; i++){
        
            for ( int j = 0; j < x[0].length; j++){

                 single[counter] = x[i][j];
                 counter++;
            }
        }
        output(single);
        
        return single;
    }
    
    public static void output( int x[]){
    
        for (int i =0; i < x.length; i++){
        
            System.out.println(x[i]);
        }
    }

Algorihm that finding number index of an integer array with sequantial search.

public static void main(String[] args) {
        
        int list [] = { 10, 20, 30 ,40 , 50 ,60 ,70 , 80 ,90 ,100};
        
        output( find(list) );
    }
    
    public static int find( int x[]){
    
        Scanner s = new Scanner(System.in);
        
        int f = s.nextInt();
        
        for ( int i =0; i < x.length; i++){
        
            if ( f == x[i]){
            
                return (i+1);
            
            }
           
        }
        
        return 0;
    }
    
    public static void output( int x){
    
        if ( x== 0){
            System.out.println("Array doesn't have this element");
        }
        else {
            System.out.println("array has element index of " + x);
        }
    }

Algorithm that find number of an integer array with binary search.

public static void main(String[] args) {
        
        int list [] = {1 , 10, 5, 8 , 6 , 5, 3, 2, 1, 20};
        
        convertSeries(list);    
        }
    
    public static int[] convertSeries( int x[]){
    
        int keep;
        
        for ( int i =0; i < x.length; i++){
        
            for ( int j = i+1; j < x.length; j++){
            
                if ( x[i] < x[j]){
                
                    keep = x[i];
                    x[i] = x[j];
                    x[j] = keep;
                }
            }
        }
        
        check(x);
        return x;
    }
    
    public static void check (int x [] ){
    
        Scanner s = new Scanner (System.in);
        
        int f = s.nextInt();
        
        boolean condition = true;
        
        for ( int i = 0; i < x.length; i++ ){
   
            if ( f == x[i]){
            
                condition = false;
            }
        }
        
        if ( condition == false){
        
            find(x,f);
        }
        else {
            output(-1);
        }
        }
        
       public static void find (int x[], int f){
  
        boolean condition = false;
                
        int floor = 0, ceiling = x.length, counter =0;
        int keep ;
    
        for ( int i =0 ; i < x.length; i++){
            
            keep = (floor+ceiling)/2;
            
            if ( f < x[keep]){
                
                floor = keep;
                counter++;
            }
            else if ( f > x[keep]){
                
                ceiling = keep;
                counter++;
            }
            else {
                condition = true;
            }
        
        
        }
        
        if ( condition == true){
            
             output(counter);
        }
        
        }  
    
    
    public static void output( int x){
    
        if ( x == -1){
            System.out.println("This number doesn`t have array");
        }
        else {
        System.out.println("Number finding try of " + (x+1));
        }
    }

Write algorithm of selection sort.

public static void main(String[] args) {
        
        int list [] = new int[10];
        
        input(list);
    }
    
    public static int[] input(int x[]){
    
        Scanner s = new Scanner(System.in);
        
        for( int i =0; i < x.length; i++){
        
            x[i] = s.nextInt();
        }
        selectionSort(x);
        
        return x;
    }
    
    public static void selectionSort ( int x[] ){
    
        int keep ;
        
        for ( int i = 0 ; i < x.length; i++){
        
            for ( int j = i+1; j < x.length; j++ ){
            
                if ( x[i] < x[j]){
                    
                    keep = x[i];
                    x[i] = x[j];
                    x[j] = keep;
                
                }
            }
        }
        
        output(x);
    }
    public static void output( int x []){
        
        for ( int i =0 ; i < x.length; i++){
        
            System.out.print(x[i] + " ");
        }
    
    }

Write algorithm of bubble sort.

public static void main(String[] args) {
        
        int x [] = new int [10];
        
        input(x);
    }
    
    public static int[] input( int x[]){
    
        Scanner s = new Scanner(System.in);
        
        for( int i = 0; i< x.length; i++){
        
            x[i] = s.nextInt();
        
        }
        bubble(x);
        
        return x;
    }
    
    public static void bubble(int x[]){
        
        int keep;
    
    for ( int i =0; i < x.length;i++){
    
        for ( int j = 0; j < x.length-1; j++){
        
            if ( x[j] > x[j+1] ){
            
                keep = x[j];
                x[j] = x[j+1];
                x[j+1] = keep;
            }
        }
    }
    
        output(x);
    }
    
    public static void output(int x[]){
    
        for ( int i =0; i< x.length; i++){
        
            System.out.print(x[i] + " ");
        }
    }

Write algorithm of insertion sort.

 public static void main(String[] args) {
        
        int list [] = { 10, 4, 7, 9, 11, 15, 3, 2}; 
        
        insertionSort(list);
    }
    
    public static int[] insertionSort(int x[]){
        
        int keep;
        
        for ( int i = 1; i < x.length; i++ ){
    
            for ( int j = 0; j < i; j++ ){
            
                if ( x[i] < x[j]){
                
                    keep = x[i];
                    x[i] = x[j];
                    x[j] = keep;
                }
            }
    
    }
        output(x);
        return x;
    }
    public static void output(int x[]){
    
        for ( int i =0; i < x.length; i++){
            
            System.out.println(x[i]);
        }
    }

Strings are entered from keyboard. The method that converts these strings to 10 4-letter words.

    public static void main(String[] args) {

        char c[] = new char[40];

        sideBySide(c);
    }

    public static void sideBySide(char c[]) {

        Scanner s = new Scanner(System.in);

        int charCounter = 0;

        for (;;) {

            String word = s.next();

            for (int i = 0; i < word.length(); i++) {

                if (word.charAt(i) != ' ') {

                    c[charCounter] = word.charAt(i);

                    charCounter++;

                    if (charCounter >= 40) {

                        print(c);
                        System.exit(1);
                    }
                }
            }
        }
    }

    public static void print(char c[]) {

        int counter = 0;

        for (;;) {

            for (int j = 0; j < 4; j++) {

                System.out.print(c[counter]);

                counter++;

                if (counter == 40) {

                    System.out.println(" ");
                    System.exit(0);
                }
            }
            
            System.out.print(" ");
        }
    }

Creating 100 8-letter passaword using English alphabet with lower case and 0-9 numbers.

public static void main(String[] args) {

        String list[] = new String[100];

        elements(list);

        print(list);
    }

    public static String[] elements(String[] x) {

        Random r = new Random();

        int trueOrFalse;
        int keepNum;
        int rndChar;
        char keepChar;

        String keep = "";

        for (int j = 0; j < x.length; j++) {

            for (int i = 0; i < 8; i++) {

                trueOrFalse = r.nextInt(2);
                keepNum = r.nextInt(10);
                rndChar = r.nextInt(123 - 97) + 97;
                keepChar = ((char) rndChar);

                if (trueOrFalse == 0) {

                    keep += keepChar;
                } else {
                    keep += keepNum;
                }
            }

            x[j] = keep;
            keep = "";

        }

        return x;
    }

Algorithm that check symmetrical or not of matrix.

public static void main(String[] args) {

        int list[][] = {{1, 3, 3, 3, 1},
                        {2, 5, 5, 5, 2},
                        {1, 3, 3, 3, 1}};

        boolean c = check(list);

        print(c);
    }

    public static boolean check(int x[][]) {

        boolean condition = true;

        for (int i = 0; i < x.length; i++) {

            for (int f = 0, l = x[0].length - 1; f < x[0].length; f++, l--) {

                if (x[i][f] != x[i][l]) {

                    condition = false;
                }

            }
        }

        for (int s = 0, f = x.length - 1; s < x.length; s++, f--) {

            for (int i = 0; i < x[0].length; i++) {

                if (x[s][i] != x[f][i]) {

                    condition = false;
                }
            }
        }

        return condition;
    }

    public static void print(boolean condition) {

        if (condition == true) {

            System.out.println("Matrix is symmetrical");
        } else {

            System.out.println("Matrinx isn't symmetrical");
        }

    }

Write a method that returns the sum of two integers that comes as a parameter

    
    public static int sum (int x , int y){
    
        return (x+y);
   
    
    }
    
    public static void main(String[] args) {
        
        Scanner s  = new Scanner(System.in);
        
        int number1 = s.nextInt();
        int number2 = s.nextInt();
        
        System.out.println(sum(number1,number2));
        
        
        
    }
    
}

Write method that returns the power of one integer other integer that comes as a parameter

public class question2 {
    
    public static int pwr (int x , int y) {
    
        int c = (int) Math.pow(x,y);
        
    return c;
    
    
    }
    
    
    public static void main(String[] args){
    
        Scanner s = new Scanner(System.in);
        
        System.out.println("Please write one number.");
        int number1 = s.nextInt();
        System.out.println("Please write power of number.");
        int number2 = s.nextInt();
        
        System.out.println("Result = " + pwr(number1,number2));
    }
}

Write method show your name until number n that comes as a parameter

public static void show(int x){
    
    for ( int i = 1 ; i <= x; i++){
    
        System.out.println("Emirhan Aydin Cakil");
    
    }
    
    
    }
    
    public static void main(String[] args){
    
        Scanner s= new Scanner(System.in);
        
        int number = s.nextInt();
        
        show(number);
    
    }

Write method that return the how much digits of integer that comes as a parameter

 public static int digit ( int x){
    
        int counter =0;
        
        while ( x > 0){
        
            counter++;
            
            x /= 10;
        
        }
    
    return counter;
    
        
    }
    
    public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        int number = s.nextInt();
        
        System.out.println(digit(number));
        
    }

Write method that return what equals is nth of fibonacci sequence that comes as a paramter

ublic static int fibonacci ( int x){
    
        int a = 1;
        int b = 1; 
        int c =0;
        
        if ( x == 1 &&  x == 2){
            return 1;
        }
        
        
        for ( int i = 3 ; i <= x ; i++){
        
         c = a + b;
         a = b;
         b = c;
        
        
        }
    
    return c;
    
    
    }
    
    public static void main(String[] args){
    
    Scanner s = new Scanner(System.in);
    
    int n = s.nextInt();
    
    System.out.println(fibonacci(n));
    
    }

Write a method that return the factorial of integer that comes to it as a paramter

public static int factorial (int x){
    
    int fct =1 ;
    
        for ( int i =1 ; i <= x; i++){
        
        fct *= i;
        
        }
    
    return fct;
    
    
    
    }
    
    
    
    public static void main(String[] args) {
       
        Scanner s = new Scanner(System.in);
        
        int number = s.nextInt();
        
       System.out.println( factorial(number));
        
    }

Write method that return sum of all integer integer entered from keyboard that comes to is as parameter

public static int sumOfAll (int x){
    
    int sum = 0; 
    
        for ( int i = 1; i < x ; i++){
        
        sum += i;
        
        
        
        }
    
        return sum;
    }
    
    public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        int number = s.nextInt();
        
       System.out.println( sumOfAll(number) );
    }

Write a method that return finding bigger of two integer that comes to it as parameter

public static int bigger ( int x , int y){
    
        int big =0;
        
    if ( x > y){
        
        big =x;
    
    }
    else{
    
        big = y;
    }
    
    return big;
    
    
    }
    
    public static void main(String[] args) {
        
        System.out.println(bigger (4,5));
        
    }

Write method that return finding lower case in a string that comes to it as parameter

public static int lowerCase ( String x){
    
    int counter = 0;
    
    for ( int i =0 ;  i < x.length(); i++){
    
        if ( x.charAt(i) >= 'a' && x.charAt(i) <= 'z'){
        
        counter++;
        
        }
    
    }
    
    return counter;
    
    }
    
    public static void main(String[] args) {
        
        String word = "Emirhan Aydin Cakil";
        
        System.out.println(lowerCase(word));
    }

Write method that return lower cases converting to upper cases and upper cases converting to lower cases of a string that comes to it as parameter

 public static String convert ( String x){
    
        String nw = "";
        
        for ( int i =0 ; i < x.length(); i++){
     
            if ( x.charAt(i) >= 'a' && x.charAt(i) <= 'z'){
            
                char c = x.charAt(i);
                String word = String.valueOf(c);
                nw += word.toUpperCase();
            }
            else {
                char c = x.charAt(i);
                String word = String.valueOf(c);
                nw += word.toLowerCase();
            }
        
    
        }
    return nw;
    
    }
    
    public static void main(String[] args) {
        
        String sentence = "eMIRHAN aYDIN cAKIL";
        
        System.out.println(convert(sentence));
        
    }

Write method that return finding how much "aa" terms of a string that comes to it as parameter

public static int findAA ( String x ){
    
    int counter =0 ;
    
    for ( int i = 0 ; i < x.length()-1; i++){
    
        if ( x.charAt(i) == 'a' && x.charAt(i+1) == 'a' ){
        
            counter++;
        }
    
    }
    
    return counter;
    
    }
    
    
    public static void main(String[] args) {
        
        
        String word = "aa bb cc aa ee dd aaa";
        
        System.out.println(findAA(word));
    }
    

Write method that return finding bigger of length of two string that comes to it as parameter

public static boolean biggerOfStrings(String x , String y ){
     
    if ( x.length() > y.length()){
    
        return true;
    
    }
    
    return false;
    
    }
    
    public static void main(String[] args) {
        
        String sentence1 = "Emirhan Aydin Cakil";
        String sentence2 = "Emirhan Aydin";
        
        boolean condition = biggerOfStrings(sentence1, sentence2);
        
        if ( condition == true){
        
                System.out.println("String 1 bigger than String 2");
        }
        else {
                System.out.println("String 1 smaller than String 2");
        }
        
    }

Write metod that return how much word of a string that comes to it as parameter

public static int wordCount ( String x ){
    
        int counter = 1 ;
        
        for ( int i =0 ; i < x.length(); i++){
        
            if ( x.charAt(i) == ' ' ){
            
                counter++;
            
            }
        
        
        }
        
    return counter;
    
    }
    
    
    public static void main(String[] args) {
        
        String sentence = "Emirhan Aydin Cakil";
        
       System.out.println( wordCount(sentence) );
        
    }

Write metod that return finding whether 'a' terms in a string that comes to it as parameter

public static boolean findA ( String x ){
    
    
        
        for ( int i = 0; i < x.length(); i++){
        
            if ( x.charAt(i) == 'a'){
            
                return true;
            }
        
        
        }
    return false;
    
    
    }
    
    public static void main(String[] args) {
        
        Scanner s = new Scanner(System.in);
        
        String sentence = s.nextLine();
        
        boolean condition = findA(sentence);
        
        if ( condition == true){
        
            System.out.println("String has character a");
        
        }
        else {
        
            System.out.println("String hasn't character a");
        }

Write method that return whether polindrome or not that comes to it as parameter

public static boolean polindromeCheck ( String x ) {
    
       
        
        for ( int i = 0 , j = x.length()-1 ; i < x.length() ; i++ , j--){
        
          
            
                if ( x.charAt(i) != x.charAt(j)){
                    
                    return false;
                
                }
    
        }
        
        return true;
           
    }
    
    
    public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        String word = s.next();
        
        boolean a = polindromeCheck(word);
        
        if ( a == false){
        
                System.out.println("String isn't a polindrome");
        }
        else {
                System.out.println("String is a polindrome");
        }
        
    }

Write metod that return sum of array of integer that comes to it as parameter

public static int sumOfArray(int []x){
    
        int top = 0 ;
        
        for ( int i = 0 ; i < x.length; i++){
        
            top += i;
        
        }
    
        return top;
    
    }
    
    
    public static void main(String[] args) {
        
        int list [] = {1,2,3,4,5,6,7,8,9,10};
        
       System.out.println( sumOfArray(list) );
        
    }
    

Write method that return indis of lowest integer of the integer array that comes to it as parameter

 public static int findLowest ( int x []){
    
        int smallest = x[0];
        int index = 0;
        
        for ( int i =0 ; i< x.length; i++){
        
            if ( smallest > x[i]){
            
                smallest = x[i];
                index = i+1;
            }
        }
    
        return index;
    
    }
    
    public static void main(String[] args) {
        
        int list [] = { 10 ,1 , 20, -10 , 30};
        
        System.out.println("index of smallest element =" +findLowest(list));
        
    }

Write metod that return checikng whether elements serial of integer array that comes to it as parameter

public static boolean checkSerial ( int [] x){
    
        for ( int i = 0 ; i < x.length-1 ; i++ ){
        
            if ( x[i] > x[i+1]){
        
            return false;
        }
        
        }
    
    return true;
    
    }
    
    public static void main(String[] args) {
        
        Scanner s= new Scanner ( System.in);
        
        int list [] = new int[5];
        
        for ( int i = 0 ; i < list.length; i++){
        
        list[i] = s.nextInt();
        }
        
        boolean condition = checkSerial(list);
        
        if ( condition == true){
        
            System.out.println("Array is an serial array");
        }
        else {
            System.out.println("Array isn't an serial array");
        }

Write metod that return plus one to all elements of integer array that comes to it as paramaeter

public static int[] plusOne(int[] x){
    
        for ( int i =0 ; i < x.length; i++){
        
            x[i]++;
        }
    
        return x;
    }
    
    public static void main(String[] args) {
        
        int [] list = {10, 20, 30, 40, 50, 60 ,70, 80 , 90 ,100};
        
        list = plusOne(list);
        
        for ( int i =0 ; i < list.length; i++){
        
            System.out.println(list[i]);
        }
        
    }

Write method that return index of longest string of string array that comes to it as a parameter

 public static int findLongest(String [] x){
    
        int length = x[0].length();
        int index = 0;
        
        
        for (int i = 0 ; i < x.length; i++){
            
           
             if ( length < x[i].length()){
                 
                 index =i;
             
            }
        
        }
    
        return index;
    }
    
    public static void main(String[] args){
    
    String list[] = {"Emirhan" , "Aydin", "Cakil"};
    
        System.out.println("indis of longest string = " + findLongest(list) );
    
    }

Write method that return second largest number of integer array that comes to it as a parameter

 public static int find ( int[] x){
   
       
       int keep;
       
       for (int i =0 ; i < x.length; i++){
       
           for ( int j = i+1 ; j < x.length; j++){
       if ( x[i] < x[j]){
           
           keep = x[i];
           x[i] = x[j];
           x[j] = keep;
           
       
                   
                   }
           }
           
       }
       
       return x[1];
   
   }
   
   public static void main(String[] args) {
       
       Scanner s= new Scanner (System.in);
       
       int [] list= new int [5];
       
       for ( int i = 0 ; i < list.length; i++){
       
           list[i] = s.nextInt();
       }
       
      System.out.println( "En buyuk 2. eleman =" + find (list) );
       
       
   }

Write method that return finding smallest and biggest elements of integer array that comes to it as a parameter

 public static int[] find ( int[] x){
   
       int smallest = x[0], biggest = x[0];
       int [] rtrn = new int[2];
       
       for ( int i =0 ; i < x.length; i++){
       
           if ( biggest < x[i]){
           
               biggest = x[i];
           }
           if ( smallest > x[i]){
           
               smallest = x[i];
               
           }
       }
       
       rtrn[0] = biggest;
       rtrn[1] = smallest;
       
       return rtrn;
   
   }
   
   
   public static void main(String[] args) {
       
       Scanner s = new Scanner(System.in);
       
       int list [] = new int [5];
       
       
       for ( int i = 0 ; i < list.length; i++){
       
           list[i] = s.nextInt();
       
       }
       System.out.println("Biggest element of array = " + find(list)[0]);
       System.out.println("Lowest element of arrat = " + find(list)[1]);
       
       
   }

Write method that returns calculate average of midterm and final exams of two arrays that comes to it as a parameter

  public static int [] calculateAverage ( int []x , int []y){
   
       int [] averages = new int [3];
       
       for ( int i =0; i < averages.length; i++){
       
           averages[i] = ((x[i]*40 )+ (y[i]*60))/100;
       
       }
   
       return averages;
   }
   
   public static void main(String[] args) {
       
       int midterms [] = {15 , 58 , 50};
       int f1nals [] = { 100 , 50, 8};
       
       for ( int i =0 ; i < midterms.length; i++){
       
           System.out.println(calculateAverage ( midterms, f1nals)[i]);
           
       
       }
   }

write method that returns finding biggest element of double dimensional array that comes to it as a parameter

that returns index of biggest element

that returns sum of each rows

 public static int biggest( int x [][]){
    
        int big = x[0][0];
    
        for ( int i =0 ; i < x.length; i++){
            for ( int j = 0 ; j < x[0].length; j++ ){
            
                if ( x[i][j] > big){
                
                    big = x[i][j];
                
                }
            
            
            }
        }
      
        
        return big;
    
    }
    
    public static int[] index ( int x[][]){
        
        int big = x[0][0];
        int index1 =0, index2=0;
        int ind [] = new int [2];
        
        for ( int i =0 ; i < x.length; i++){
            for ( int j = 0 ; j < x[0].length; j++ ){
            
                if ( x[i][j] > big){
                
                    big = x[i][j];
                    index1 = i;
                    index2 = j;
                }
            
            
            }
        }
       ind [0] = index1;
       ind [1] = index2;
        
        return ind;
    
    }
    
    public static int[] sumOfRows (int x[][]){
    
        int sum = 0 ;
        int sumRows [] = new int[2];
        
        for ( int i = 0 ; i < x.length; i++){
            for ( int j = 0; j < x[0].length; j++){
            
                sum += x[i][j];
                sumRows [i] = sum;
            }
            sum =0;
        
        }
        
        return sumRows;
    
    }
    
    
    
    public static void main(String[] args) {
        
        Scanner s = new Scanner ( System.in );
        
        int twoDimensional[][] = new int [2][2];
        
        for ( int  i = 0 ; i < twoDimensional.length; i++ ){
        
            for ( int j = 0 ; j < twoDimensional[0].length; j++){
            
            twoDimensional[i][j] = s.nextInt();
            
            }
        }
        
        System.out.println("Biggest element of double dimensional array =" + biggest(twoDimensional) );
        System.out.println("Index of biggest element of double dimensional array =" + index(twoDimensional)[0] + " " +index(twoDimensional)[1]);
        
        for ( int i = 0 ; i < 2; i++){
            
        System.out.println("Sum of "+ i +". rows of double dimensional array =" + sumOfRows(twoDimensional)[i]);
        
        }
    
    }

Write method this return longest string of double dimensional array that comes to it as a parameter

public static String longest ( String x [][]){
   
       int lng = x[0][0].length(); 
       String word = "";
       
       for ( int i = 0 ; i < x.length; i++){
       
           for ( int j = 0 ; j < x[0].length; j++){
           
               if ( lng < x[i][j].length()){
               
                   lng = x[i][j].length();
                   word = x[i][j];
               }
           
           
           }
       
       }
   
       return word;
   
   
   }
   
   public static void main(String[] args) {
       
       String str [][] = { {"Emirhan" , "Aydin" , "Cakil"},
                           {"Wesley", "Benjamin", "Sneijder"},
                           {"Sokrates" , "Platon" , "Descardes"}}; 
       
       System.out.println(longest(str));
   }

Write method that return sum of 3x3 matrix that comes to it as a parameter

 public static int sumOfMatrix ( int x [][]){
   
       int sum = 0; 
       
       for ( int i = 0 ; i < x.length; i++){
           
           for ( int j= 0 ; j < x[0].length; j++){
           
               sum += x[i][j];
           
           }
       }
   
       return sum;
   
   }
   
   
   
   public static void main(String[] args) {
       
       Scanner s = new Scanner (System.in);
       
       int matrix[][] = new int [3][3];
       
       for ( int i = 0 ; i < matrix.length; i++){
       
           for ( int j = 0 ; j < matrix[0].length; j++){
           
           matrix [i][j] = s.nextInt();
           }
       }
       System.out.println( sumOfMatrix(matrix));
       
   }

Write method that return shifting one right of integer array that comes to it as a parameter

 
   public static int[] shifting ( int x[] ){
   
       int keep;
      
       
       keep = x[9];
       
       for ( int i =x.length-1; i > 0; i--){
       
           x[i] = x[i-1];
          
       }
   
       x[0] = keep;
     
       return x;
   
   }
   
   public static void main(String[] args) {
       
       int [] list = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
       
       int [] list2 = shifting(list);
       
     for ( int i =0; i < list2.length; i++){
       
           System.out.print( list2[i] + " ");
       }
       
   }

Write method that return sum of two arrays with 10 elemenst that comes to it as a parameter

public static int sumOfArrays ( int x[], int y[]){
   
       int sum = 0;
       
       for ( int i =0 ; i < x.length; i++){
       
           for ( int j = 0; j < y.length; j++){
           
            sum += x[i] + y[j];
           
           
           }
       
       
       }
   
       return sum;
   
   }
   
   
   public static void main(String[] args) {
       
       int [] list1 = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
       int [] list2 = {10 , 20, 30, 40, 50, 60, 70, 80, 90, 100};
           
           System.out.println( sumOfArrays(list1, list2));
       
   }

Write method that returns check whether prime number or not that comes to it as a parameter

public static boolean check ( int x){
   
       for ( int i = 2 ; i < x; i++){
       
          if ( x % i == 0){
          
              return false;
          }
       
       }
   return true;
   
   }
   
   public static void main(String[] args) {
       
       Scanner s = new Scanner(System.in);
       
       int number = s.nextInt();
       
       boolean condition = check(number);
       
       if ( condition == true ){
       
               System.out.println("Number is a prime number");
       }
       else {
               System.out.println("Number isn't a prime number");
       }
       
       
   }

Write method that return calculate average of odd numbers of a integer array that comes to it as a parameter

public static double averageOdd ( int []x) {
    
        double avg , counter = 0 , sum =0;
        
        
        for ( int i =0; i < x.length; i++){
        
            if ( x[i] % 2 != 0){
                
                sum += x[i];
                counter++;
            
            }
        
        }
        
        if ( counter == 0){
            return 0;
        }
        else {
            
          avg = sum/counter;
       
        }
    
        return avg;
    }
    
    public static void main(String[] args) {
        
        int list[] = { 1,2,3,4,5,6,7,8,9,10};
        
        System.out.println( averageOdd(list));
        
    }

Write method that returns finding longest word and indexs this of a double dimension array that comes to it as a parameter

public static String[] find ( String[][] x){
    
        String lngst = x[0][0];
        int longest  = x[0][0].length(), indexA = 0, indexB = 0 ;
        
        for ( int i =0; i < x.length; i++){
            
            for ( int j =0; j< x[0].length; j++){
            
            if ( longest < x[i][j].length() ){
            
                longest = x[i][j].length();
                lngst = x[i][j];
                indexA = i;
                indexB = j;
                
            }
      
            }
        
        }
        String i = String.valueOf(indexA);  
        String j = String.valueOf(indexB);
        
        String finded [] = {lngst, i, j};
    
        return finded;
    }
    
    public static void main(String[] args) {
        
        
        
        Scanner s = new Scanner(System.in);
        
        String list [][] = new String[2][2];
        
        for ( int i = 0; i < list.length; i++){
        
            for ( int j = 0 ; j < list[0].length; j++){
            
            list[i][j] = s.next();
            
            }
        }
        
        System.out.println("Longest String = " + find(list)[0] + " Indis =" + find(list)[1] + ", " + find(list)[2]);
    }

Recursive method that prints your name on your screen 5 times.

    public static void main(String[] args) {
        
        String name = "Emirhan Aydin Cakil";
                
        print (name , 5 );        
    }
    
    public static int print ( String name, int x){
    
        if ( x == 0){
            
            return 0;
        }
        
        System.out.println(name);
        
        return print (name , --x);
    
    }

Recursive method that sum of between integers of 1 - 5.

  public static void main(String[] args) {
        
        System.out.println(sum(5));
        
    }
    
    public static int sum ( int x ){
    
        if ( x == 1){
            
            return 1;
        }
        
        return x + sum( --x);
    }

Recursive method that sum of integers divisible of 7 between of 1 to 100.

 public static void main(String[] args) {
        
        System.out.println( sum (100) );
    }
    
    public static int sum ( int x ){
    
        if ( x == 0){
        
            return 0;
        }
        
        if ( x % 7 == 0){
            
            return x + sum (--x);
        }
        
        return sum (--x);
    }

Same index and same value of two integer arrays.

a) Recursive method that prints this values on your screen.

b) Recursive method that sum of this values.

c) Recursive method that finding how much this values.

public static void main(String[] args) {
        
        int arrayA []= {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
        
        int arrayB []= {10, 23, 9 , 40, 32, 90, 70, 1, 20, 100};
        
       print ( arrayA, arrayB , 0);
       
     
    }
    
    public static int print ( int x [], int y[], int i ){
    
        if ( i == x.length){
            
              System.out.println("Sum of sames = " + calculate ( x, y , 0));
              System.out.println("Number of sames = " + counter ( x, y , 0 , 0));
            
            System.exit(0);
    }
    
        if ( x[i] == y[i]){
        
            System.out.println(x[i]);
        }
        
        return print ( x, y, ++i);
    }
    
    public static int calculate (int x[], int y [], int i){
    
        if ( i == x.length){
   
            return 0;        
        }
        
        if ( x[i] == y[i]){
        
           return  x[i] + calculate (x , y , ++i);
            
        }
        return calculate (x, y , ++i);
    }
    
    public static int counter (int x[], int y[], int i , int counter){
    
        if ( i == x.length){
        
            return counter;
        }
        
        if ( x[i] == y[i]){
            
            return counter ( x, y, ++i, ++counter);
            
        }
        
        return counter ( x, y, ++i, counter);
    
    }

Recursive method that calculate factorial that comes to as parameter.

 public static void main(String[] args) {
        
        Scanner s = new Scanner ( System.in );
        
        int number = s.nextInt();
        
        System.out.println( factorial(number) );
        
    }
    
    public static int factorial ( int x){
    
        if ( x == 1){
        
            return 1;
        }
    
        return x * factorial ( --x );
    }

Recursive method that finding how many digits of number.

public static void main(String[] args) {
        
        Scanner s = new Scanner ( System.in );
        
        int number = s.nextInt();
        
        System.out.println( digit ( number , 0) );
        
    }
    
    public static int digit ( int x, int counter ){
    
        if ( x== 0 ){
        
            return counter;
        }
        x /= 10;
        return digit (x , ++counter);
    }

Recursive mathod that calculate power of coming two number from keyboard.

 public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        int base = s.nextInt();
        
        int pwr = s.nextInt();
        
        System.out.println(calculate ( base, pwr));
    }
    
    public static int calculate ( int x , int y ){
    
        if ( y == 1){
        
            return x;
        }
        
        return x * calculate ( x, --y);
    }

Recursive method that finding value of fibonacci elements.

public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        int number = s.nextInt();
        
        System.out.println(fibonacci (number));
    }
    
    public static int fibonacci ( int x ){
    
    if ( x == 1 || x == 2){
    
        return 1;
    }
    
    return fibonacci (x-2) + fibonacci (x-1);
    }

Recursive method that finding biggest element of integer array.

public static void main(String[] args) {
        
        int [] list = { 9, 101, 10, 23, 24, 1, 11, 3, 4};
        
        System.out.println("index of biggest element = " + find(list , 0 , list[0] , 0) );
        
    }
    
    public static int find ( int x[] , int i , int biggest , int index){
    
        if ( i == x.length){
        
            return index+1;
        }
        
        if ( biggest < x[i]){
            
            biggest = x[i];
            index = i;
        }
        
        return find ( x , ++i, biggest, index);
    }

Recursive method that checking series or not of integer array.

  public static void main(String[] args) {
        
        
        int list[] = new int [5];
        
        elements ( list);
        
        if ( check(list , 0) == 1 ){ 
        
            System.out.println("Array isn't a series");
        }
        
        else {
        
            System.out.println("Array is a series");
        }
    }
    
    public static int [] elements (int []x){
    
        Scanner s = new Scanner (System.in);
        
        for ( int i =0 ; i < x.length; i++){
        
            x[i] = s.nextInt();
        }
        
        return x;
    
    }
    
    public static int check ( int x[], int i ){
    
        if ( i == x.length-1){
        
            return 0;
        }
        
        if ( x[i+1] > x[i]){
        
            return check (x, ++i);
        }
        
        return 1;
    }

Recursive method that check symmetrical or not of a array.

public static void main(String[] args) {
        
        int list[] = new int [5];
        
        elements ( list);
        
       if ( check (list , 0, list.length-1) == 0 ){
       
           System.out.println("List is symmetrical");
       }
       else {
           
           System.out.println("List isn't symmetrical");
        }
    }
    
    public static int[] elements( int x[]){
           
        Scanner s = new Scanner (System.in);
        
        for (int i = 0 ; i < x.length; i++){
        
            x[i] = s.nextInt();
        }
        
        return x;
    }
    
    
    public static int check ( int x[] , int i , int j){
    
        if ( i == x.length-1){
        
            return 0;
        }
        
        if ( x[i] != x[j] ){
        
            return 1;
        }
        
        return check ( x, ++i, --j);
    }

Recursive method that finding how many positive integer of integer array has.

 public static void main(String[] args) {
        
        int list []= {1, -1, 2, -2, 3, -3, 4, -4, 5, -5};
        
        System.out.println("Number of positives = " + find (list , 0 , 0));
        
    }
    
    public static int find ( int x[], int i, int counter){
    
        if ( i == x.length){
        
            return counter;
        }
        
        if ( x[i] > 0) {
        
            return find (x, ++i , ++counter);
        }
        
        return find ( x, ++i , counter);
    }

Recursive method that finding how many lower case of string array has.

public static void main(String[] args) {
        
        String [] sentence =  {"Emirhan", "Aydin", "Cakil"};
        
        System.out.println("Number of lower cases = " + find (sentence , 0 , 0 , 0));
        
    }
    
    public static int find ( String x [], int i, int j, int counter ){
    
        if ( i == x.length){
        
            return counter;
        }
        
        if ( j == x[i].length()){
            
            return find (x, ++i, 0, counter);
        }
        
        
        if ( x[i].charAt(j) >= 'a' && x[i].charAt(j) <= 'z'){
        
            return find (x, i, ++j, ++counter);
        }
        else {
            return find (x, i, ++j, counter);
        }
    }

Recursive method that reverses elements of an array.

public static void main(String[] args) {
        
        String list []= {"Emirhan", "Aydin" , "Cakil"};
        
        String keep = "";
        
        reverse ( list , keep , 0 , list.length-1);
    }
    
    public static int reverse (String [] x , String keep,  int i , int j){
    
        if ( i == x.length/2 ){
        
            print (x);
            return 0;
        }
        
        keep = x[j];
        x[j] = x[i];
        x[i] = keep;
        
        return reverse ( x, keep , ++i, --j);
    }
    
    public static void print ( String []x){
    
        for ( int i = 0 ; i < x.length; i++){
        
            System.out.println(x[i]);
        }
    }

Recursive method that reverses string.

public static void main(String[] args) {
        
        Scanner s = new Scanner (System.in);
        
        String rev = "";
        
        String sentence = s.nextLine();
        
        System.out.println(reverse (sentence , rev ,sentence.length()-1 ) );
    }
    
    public static String reverse (String x ,String y, int i ){
    
        if ( i == -1){
            
            return y;
        }
        
        y += x.charAt(i);
      
        return reverse ( x, y , --i);
    }

Strings are entered from keyboard. The method that converts these strings to 10 sentences with 4 words.

 public static void main(String[] args) {

        String list[] = new String[40];

        elements(list);

    }

    public static void elements(String x[]) {

        Scanner s = new Scanner(System.in);

        int i = 0;

        for (;;) {

            x[i] = s.next();
            i++;

            if (i == x.length) {

                print(x);
                System.exit(1);

            }

        }

    }

    public static void print(String x[]) {

        Random r = new Random();

        int rnd;
        int names;

        int counter = 0;
        int finishCounter = 0;

        while (finishCounter < 10) {

            rnd = r.nextInt(4) + 1;
            

            for (int i = 0; i < rnd; i++) {

                names = r.nextInt (40)+1;
                System.out.print(x[names] + " ");
                
            }
            finishCounter++;
            System.out.println(" ");

        }

        System.exit(0);
    }

Creating with using recursive method 100 8-letter passaword using English alphabet with lower case and 0-9 numbers.

public static void main(String[] args) {

        String list[] = new String[100];
        String none = "";
        Random r = new Random();

        create(list, 0, 0, none, r);

        print(list, 0);
    }

    public static String[] create(String x[], int i, int j, String keep, Random r) {

        if (j == x.length) {

            return x;
        }
        if (i < 8) {

            if (condition(0, r) == 0) {

                keep += rndNum(0, r);
            } else {
                keep += rndChar((char) 0, 0, r);
            }

            return create(x, ++i, j, keep, r);

        } else {
    
            x[j] = keep;
            keep = "";
            return create(x, 0, ++j, keep, r);
        }

    }

    public static char rndChar(char keepC, int rnd, Random r) {

        rnd = r.nextInt(123 - 97) + 97;
        keepC = ((char) rnd);

        return keepC;
    }

    public static int rndNum(int keepNum, Random r) {

        keepNum = r.nextInt(10);

        return keepNum;
    }

    public static int condition(int trueOrFalse, Random r) {

        trueOrFalse = r.nextInt(2);

        return trueOrFalse;
    }

    public static int print(String[] x, int i) {

        if (i == x.length) {

            System.exit(0);
        }

        System.out.println((i + 1) + " " + x[i]);

        return print(x, ++i);
    }

100 strings are entered from the keyboard and these strings are combined. 20 words with 5 letters are randomly generated from these 100 strings. algorithm that prints the equal of these 20 words to the screen.

public static void main(String[] args) {

        String longString = "";

        longString = elements(longString);

        elementsOfList(longString);
    }

    public static String elements(String x) {

        Scanner s = new Scanner(System.in);

        for (int i = 0; i < 100; i++) {

            x += s.next();
        }

        return x;
    }

    public static void elementsOfList(String x) {

        Random r = new Random();

        String list[] = new String[20];
        String keep = "";

        int rnd;

        for (int i = 0; i < list.length; i++) {

            rnd = r.nextInt(x.length() - 4);

            for (int j = rnd; j < rnd + 5; j++) {

                keep += x.charAt(j);
            }
            list[i] = keep;
            keep = "";
        }
        allPrint(list);
        check(list);
    }

    public static void allPrint(String[] x) {

    // that method generated for checking list.
 
        for (int i = 0; i < x.length; i++) {

            System.out.println(x[i]);
        }
    }

    public static void check(String[] x) {

        for (int i = 0; i < x.length; i++) {

            for (int j = i + 1; j < x.length; j++) {

                if (x[i].equals(x[j])) {

                    System.out.println("same elements of random list =" + x[i]);
                }
            }
        }
    }