do-while Loop
After for loop and while loop in JavaScript , another most common loop used is do-while loop in JavaScript. The do-while loop in JavaScript is a control flow statement that allows you to execute a block of code repeatedly as long as a specified condition becomes true. Unlike other loops, the do-while loop guarantees the execution of a block of code at least once before checking the condition. It prints the statement at least once and then checks the condition.
The syntax of do-while loop in JavaScript is:
do{
//code
} while(condition);Here's how the do-while loop works:
- The code block inside the do statement is executed first, without checking any conditions.
- After executing the code block, the condition in the while statement is evaluated.
- If the condition evaluates to true, the code block is executed again. The loop continues until the condition becomes false.
- If the condition initially evaluates to false, the code block is still executed once before exiting the loop.
Example 1:
let i=0;
do{
console.log(i);
i++:
} while(i<5);0
1
2
3
4
Inference 1 : even if i which is 0 is not greater than 5 as per the given condition, do-while loop still executes the statement at least once and then checks the condition by incrementing the value.
Example 2:
let count = 1;
do {
console.log('Count:', count);
count++;
} while (count <= 5);Count: 1
Count: 2
Count: 3
Count: 4
Count: 5
Conclusion
To summarize, the do-while loop in JavaScript executes a block of code at least once, regardless of the condition. It is useful when you need to repeat a task until a specific condition is met. By understanding its syntax and usage, you can leverage the power of do-while loops in your JavaScript programs.
