While Loop in Java

The while loop contineously executes a block of statements while a particular condition is true

The structure of while loop is:

While(condition)
{
	// do something
}

Meaning of this above piece of code is: As long as the condition mentioned in the while loop holds true, the //do something part will execute. Whenever the condition becomes false, the loop will break and the control goes to the next statement after the loop.

Example

public class WhileDemo {

	// we want to print 10 to 1 backwards
	public static void main(String[] args) {
		int i = 10; // initiate the count
		
		while (i > 0) { // while checks if i is greater than 0
			System.out.print(i + " ");
			i--; // decrease the value of i by 1
		}
	}
}
Try It

The above program prints:

10 9 8 7 6 5 4 3 2 1

Why did we put i-- statement inside the while loop? What could have happened otherwise?

We need to remember that we used the condition “when I is greater than ZERO” and we initiated I with 10. SO, if we don’t put a decrement of i inside the loop, the value of i will never be changed and this can cause an infinite loop and ultimately a shutdown of JVM due to low memory space.

So, while writing the while, we must be careful that it shouldn’t create an infinite loop.


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