Do While Loop in Java

Why Do-While Loop?

• Sometimes we need a loop to execute at least once, even if the condition is false.
• do-while loop guarantees one execution first, then checks the condition.

Syntax

do {
    // statements
} while (condition);

Example 1 – Condition False but Runs Once

int i = 5;
do {
    System.out.println("Hi " + i);
} while (i <= 4);

👉 Output:

Hi 5

⚡ Even though i <= 4 is false, loop runs once.

Example 2 – Works Same as While When Condition True

int i = 1;
do {
    System.out.println("Hi " + i);
    i++;
} while (i <= 4);

👉 Output:

Hi 1
Hi 2
Hi 3
Hi 4

✅ Same result as while loop when condition is true.

Key Difference: while vs do-while

Summary:

• while → check first, then run.
• do-while → run first, then check.