minor changes

Programs/armstrong.cpp

@@ -1,26 +1,28 @@
 #include <iostream>
+#include <cmath>
 using namespace std;
 
-int main() {
-    int num, originalNum, remainder, result = 0;
+int main(void) {
+    size_t  originalNum, remainder, result = 0;
+    int input;
     cout << "Enter a three-digit integer: ";
-    cin >> num;
-    originalNum = num;
+    cin >> input;
+    originalNum = abs(input);
 
     while (originalNum != 0) {
         // remainder contains the last digit
         remainder = originalNum % 10;
 
-        result += remainder * remainder * remainder;
+        result += pow(remainder,3);
 
         // removing last digit from the orignal number
         originalNum /= 10;
     }
 
-    if (result == num)
-        cout << num << " is an Armstrong number.";
+    if (result == abs(input))
+        cout << abs(input) << " is an Armstrong number.";
     else
-        cout << num << " is not an Armstrong number.";
+        cout << abs(input) << " is not an Armstrong number.";
 
     return 0;
 }

Programs/armstrong_between_intervals.cpp

@@ -1,26 +1,30 @@
 #include <iostream>
+#include <cmath>
 using namespace std;
 
-int main()
+int main(void)
 {
-  int num1, num2, i, num, digit, sum;
+  size_t start,end, i, currentDigit, digit, sum;
+  int num1,num2;
 
   cout << "Enter first number: ";
   cin >> num1;
 
   cout << "Enter second number: ";
   cin >> num2;
 
-  cout << "Armstrong numbers between " << num1 << " and " << num2 << " are: " << endl;
-  for(i = num1; i <= num2; i++)
+  start = abs(num1);end = abs(num2);
+  cout << "Armstrong numbers between " << start << " and " << end << " are: " << endl;
+  for(i = start; i <= end; ++i)
   {
         sum = 0;
-        num = i;
+        currentDigit = i;
 
-        for(; num > 0; num /= 10)
+        while( currentDigit > 0 )
         {
-            digit = num % 10;
-            sum = sum + digit * digit * digit;
+            digit = currentDigit % 10;
+            sum += pow(digit,3);
+            currentDigit /= 10; 
         }
 
         if(sum == i)

Programs/ascii.cpp

@@ -3,9 +3,9 @@ using namespace std;
 
 int main()
 {
- char c;
- cout << "Enter a character: ";
- cin >> c;
- cout << "ASCII Value of " << c << " is " << int(c);
- return 0;
+    char c;
+    cout << "Enter a character: ";
+    cin >> c;
+    cout << "ASCII Value of " << c << " is " << int(c)<<endl;
+    return 0;
 }

Programs/bin_to_octal.cpp

@@ -3,20 +3,20 @@
 
 using namespace std;
 
-int convertBinarytoOctal(long long);
+int BinarytoOctal(long long);
 int main()
 {
     long long binaryNumber;
 
     cout << "Enter a binary number: ";
     cin >> binaryNumber;
 
-    cout << binaryNumber << " in binary = " << convertBinarytoOctal(binaryNumber) << " in octal ";
+    cout << binaryNumber << " in binary = " << BinarytoOctal(binaryNumber) << " in octal ";
 
     return 0;
 }
 
-int convertBinarytoOctal(long long binaryNumber)
+int BinarytoOctal(long long binaryNumber)
 {
     int octalNumber = 0, decimalNumber = 0, i = 0;
 

Programs/check_prime.cpp

@@ -1,35 +1,32 @@
 #include <iostream>
 using namespace std;
 
-bool checkPrimeNumber(int);
+bool isPrimeNumber(long long);
 
-int main() {
-    int n;
+int main(void) {
+    long long input;
 
     cout << "Enter a positive  integer: ";
-    cin >> n;
+    cin >> input;
 
-    if (checkPrimeNumber(n))
-        cout << n << " is a prime number.";
+    if (isPrimeNumber( input ) )
+        cout << input << " is a prime number.";
     else
-        cout << n << " is not a prime number.";
+        cout << input << " is not a prime number.";
     return 0;
 }
 
-bool checkPrimeNumber(int n) {
-    bool isPrime = true;
+bool isPrimeNumber(long long n) {
 
-    // 0 and 1 are not prime numbers
-    if (n == 0 || n == 1) {
-        isPrime = false;
+    // 0 or 1 or negative numbers are not prime numbers
+    if (n == 0 || n == 1 || n < 0) {
+        return false;
     }
-    else {
-        for (int i = 2; i <= n / 2; ++i) {
+
+        for (long long i = 2; i <= n / 2; ++i) {
             if (n % i == 0) {
-                isPrime = false;
-                break;
+                return false;
             }
         }
-    }
-    return isPrime;
+    return true;
 }

Programs/complex_num_subtr.cpp

@@ -16,7 +16,7 @@ class Complex
        }
 
        // Operator overloading
-       Complex operator - (Complex c2)
+       Complex operator - (Complex const &c2)
        {
            Complex temp;
            temp.real = real - c2.real;
@@ -38,10 +38,10 @@ int main()
 {
     Complex c1, c2, result;
 
-    cout<<"Enter first complex number:\n";
+    cout<<"Enter first complex number\n";
     c1.input();
 
-    cout<<"Enter second complex number:\n";
+    cout<<"Enter second complex number\n";
     c2.input();
 
     // In case of operator overloading of binary operators in C++ programming, 

Programs/convert_bin_to_dec.cpp

@@ -3,20 +3,20 @@
 
 using namespace std;
 
-int convertBinaryToDecimal(long long);
+int BinaryToDecimal(long long);
 
-int main()
+int main(void)
 {
     long long n;
 
     cout << "Enter a binary number: ";
     cin >> n;
 
-    cout << n << " in binary = " << convertBinaryToDecimal(n) << "in decimal";
+    cout << n << " in binary = " << BinaryToDecimal(n) << "in decimal";
     return 0;
 }
 
-int convertBinaryToDecimal(long long n)
+int BinaryToDecimal(long long n)
 {
     int decimalNumber = 0, i = 0, remainder;
     while (n!=0)

Programs/fact_recur.cpp

@@ -1,21 +1,26 @@
+//working till 65
 #include<iostream>
+#include <cmath>
 using namespace std;
 
-int factorial(int n);
+unsigned long long factorial(unsigned long long n);
 
 int main()
 {
-    int n;
+    long long input;
 
     cout << "Enter a positive integer: ";
-    cin >> n;
+    cin >> input;
 
-    cout << "Factorial of " << n << " = " << factorial(n);
+    if(input <= 20)
+        cout << "Factorial of " << llabs(input) << " = " << factorial( llabs(input) );
+    else
+        cout << "Results are too long to calculate!";    
 
     return 0;
 }
 
-int factorial(int n)
+unsigned long long factorial(unsigned long long n)
 {
     if(n > 1)
         return n * factorial(n - 1);

Programs/factorial.cpp

@@ -3,13 +3,18 @@ using namespace std;
 
 int main()
 {
-    unsigned int n;
+    unsigned n;
     unsigned long long factorial = 1;
 
     cout << "Enter a positive integer: ";
     cin >> n;
+
+    if(n > 20){
+        cout << "Results are too long to calculate!";
+        return 0;
+    }
 
-    for(int i = 1; i <=n; ++i)
+    for(unsigned i = 1; i <=n; ++i)
     {
         factorial *= i;
     }

Programs/factors.cpp

@@ -3,7 +3,7 @@ using namespace std;
 
 int main()
 {
-    int n, i;
+    unsigned long long n, i;
 
     cout << "Enter a positive integer: ";
     cin >> n;

Programs/fibb.cpp

@@ -3,31 +3,31 @@ using namespace std;
 
 int main()
 {
-    int n, t1 = 0, t2 = 1, nextTerm = 0;
+    unsigned long long n, t1 = 0, t2 = 1, nextTerm = 0;
 
     cout << "Enter the number of terms: ";
     cin >> n;
 
     cout << "Fibonacci Series: ";
-
+
+
     for (int i = 1; i <= n; ++i)
     {
-        // Prints the first two terms.
         if(i == 1)
         {
             cout << " " << t1;
             continue;
         }
         if(i == 2)
         {
-            cout << t2 << " ";
+            cout <<" "<<t2 << " ";
             continue;
         }
         nextTerm = t1 + t2;
         t1 = t2;
         t2 = nextTerm;
 
         cout << nextTerm << " ";
-    }
+    }  
     return 0;
 }

Programs/gcd.cpp

@@ -16,6 +16,6 @@ int main()
             n2 -= n1;
     }
 
-    cout << "HCF = " << n1;
+    cout << "GCF = " << n1;
     return 0;
 }

Programs/hello_world.cpp

@@ -1,8 +1,8 @@
 // Your First C++ Program
-
 #include <iostream>
-using namsespace std;
+using namespace std;
+
 int main() {
     cout << "Hello World!";
     return 0;
-}
+}

Programs/palindrom_num.cpp

@@ -14,7 +14,7 @@ int main()
      {
          digit = num % 10;
          rev = (rev * 10) + digit;
-         num = num / 10;
+         num /= 10;
      } while (num != 0);
 
      cout << " The reverse of the number is: " << rev << endl;