Understanding while loop in Java

• While loop works very similar to for loop.
• The only difference between for loop and while loop is the positioning of initialization, evaluation and expression evaluation section.
• While loop only takes boolean Type as the condition argument OR an expression resulting in a boolean value. Any other Type like int , long is not acceptable.

Lets take examples to understand while loop

• Classical while loop

 public void loop1() {

        // initialization
        int i = 2;

        // condition check
        while (i >= 0) {
            System.out.println("Inside LOOP1 value of i is " + i);
            i--;   // expression evaluation
        }

    }

Inside LOOP1 value of i is 2
Inside LOOP1 value of i is 1
Inside LOOP1 value of i is 0

[addToAppearHere]

• Infinite While loop

 public void loop2() {

        // infinete while loop
        // condition check
        while (Boolean.TRUE) {
            System.out.println("Inside infinite while loop");
        }
    }

• While loop with a method in the conditional check

 private int getConditionaValue() {
        System.out.println("I am inside the getConditionaValue method");
        return 0;
    }
    

 public void loop3() {

        int i = 3;
        // condition check
        while (i >= getConditionaValue()) {
            System.out.println("Inside LOOP3 value of i is " + i);
            i--;
        }

    }


I am inside the getConditionaValue method
Inside LOOP3 value of i is 3
I am inside the getConditionaValue method
Inside LOOP3 value of i is 2
I am inside the getConditionaValue method
Inside LOOP3 value of i is 1
I am inside the getConditionaValue method
Inside LOOP3 value of i is 0
I am inside the getConditionaValue method