What is the difference between while and do-while loops in Java?

Understanding the Difference Between while and do-while Loops in Java

In Java, both the while and do-while loops are used to repeatedly execute a block of code, but they differ in their execution flow and behavior.

while Loop

The while loop in Java is a pre-test loop, which means the condition is evaluated before the loop body is executed. The general syntax of a while loop is:

while (condition) {
    // loop body
}

Here's an example:

int count = 0;
while (count < 5) {
    System.out.println("Count: " + count);
    count++;
}

In this example, the loop will execute as long as the count variable is less than 5. The loop will continue to execute until the condition becomes false.

do-while Loop

The do-while loop in Java is a post-test loop, which means the loop body is executed at least once, and then the condition is evaluated. The general syntax of a do-while loop is:

do {
    // loop body
} while (condition);

Here's an example:

int count = 0;
do {
    System.out.println("Count: " + count);
    count++;
} while (count < 5);

In this example, the loop body will execute at least once, and then the condition count < 5 will be evaluated. The loop will continue to execute until the condition becomes false.

The main difference between while and do-while loops is that the do-while loop will always execute the loop body at least once, even if the condition is false. In contrast, the while loop will not execute the loop body if the condition is false from the beginning.

In summary, the while loop is a pre-test loop, while the do-while loop is a post-test loop. The choice between the two depends on the specific requirements of your program and the logic you want to implement.