Java Loop

In Java, loops are used to repeatedly execute a block of code until a certain condition is met. They provide a way to perform repetitive tasks efficiently and with less code. Java provides three types of loops: for, while, and do-while. Let's explain each of them:

1. for Loop: The for loop is used when the number of iterations is known beforehand or when iterating over a collection/array. It consists of three parts: initialization, condition, and iteration expression.

   for (initialization; condition; iteration) {
       // Code to be executed in each iteration
   }

   The initialization statement is executed only once at the beginning. The condition is checked before each iteration, and if it evaluates to true, the code block is executed. After each iteration, the iteration statement is executed, and then the condition is checked again. The loop continues until the condition evaluates to false.

3. while Loop: The while loop is used when the number of iterations is not known beforehand and depends on a condition. It repeatedly executes the code block as long as the condition is true.

   while (condition) {
       // Code to be executed in each iteration
   }

   The condition is evaluated before each iteration. If it evaluates to true, the code block is executed. If it evaluates to false initially, the code block is never executed.

5. do-while Loop: The do-while loop is similar to the while loop, but the condition is checked at the end of the loop, ensuring that the code block is executed at least once.

   do {
       // Code to be executed in each iteration
   } while (condition);

   The code block is executed first, and then the condition is checked. If the condition evaluates to true, the loop continues for subsequent iterations. If the condition evaluates to false, the loop terminates.

   

Loop control statements like break and continue can be used to control the flow of execution within loops. break is used to exit the loop completely, while continue skips the rest of the current iteration and proceeds to the next iteration.

Here's an example that demonstrates the use of different loops:

for (int i = 1; i <= 5; i++) {
    System.out.println("Value of i: " + i);
}

int j = 1;
while (j <= 5) {
    System.out.println("Value of j: " + j);
    j++;
}

int k = 1;
do {
    System.out.println("Value of k: " + k);
    k++;
} while (k <= 5);

In this example, each loop prints the values of a variable (i, j, and k) from 1 to 5. The output will display:

Value of i: 1
Value of i: 2
Value of i: 3
Value of i: 4
Value of i: 5

Value of j: 1
Value of j: 2
Value of j: 3
Value of j: 4
Value of j: 5

Value of k: 1
Value of k: 2
Value of k: 3
Value of k: 4
Value of k: 5

Loops provide a powerful mechanism for automating repetitive tasks and iterating over collections, making them an essential part of programming in Java.

Assignment Day 5

1. Java Program to Display Alphabets (A to Z) using loop

  A,B,C.....

2. Java Program to Count Number of Digits in an Integer

  Enter Number : 9876
  your digits count : 4

3. Write a program that prompts the user to input an integer and then outputs the number with the digits reversed. For example, if the input is 12345, the output should be 54321.

  Enter Number : 9876
  your Recerse Number : 6789

4. Program to print half pyramid using alphabets
   

    A
    B B
    C C C
    D D D D
    E E E E E
    

5. Write a program that reads a set of integers, and then prints the sum of the even and odd integers.(noote : also find sum of the total number : )

 Enter Start Loop Number : 1
 Emter End Loop Number : 10

 Sum of the total Number = 55
 Sum of the Even Number = 30
 Sum of the Odd Number = 25

8. Write a program to print table :

 Enter Print Table : 2
 2 x 1 = 2
 2 x 2 = 4
 .
 .
 2 x 10 = 20

9. Write a program to print following :