JavaScript Do While Loop

In JavaScript, the do-while loop is a control flow statement that is similar to the while loop. The main difference is that the do-while loop executes the code block at least once, regardless of the condition. After the first iteration, the condition is evaluated, and if it is true, the loop continues executing. If the condition is false, the loop is exited.

The syntax of a do-while loop is as follows:

do {

  // code to be executed

} while (condition);

Here's how a do-while loop works:

1. The code block inside the do statement is executed first.

2. After executing the code block, the program evaluates the condition.

3. If the condition is true, the loop continues, and the program returns to the beginning of the do statement, executing the code block again. This process repeats until the condition becomes false.

4. If the condition is false, the loop is exited, and the program continues with the next statement after the loop.

Here's an example of a do-while loop that counts from 1 to 5:

var i = 1;

do {

  console.log(i);

  i++;

} while (i <= 5);

In the example above, the code block inside the do statement is executed first, which prints the value of i to the console. After that, i is incremented by 1 with i++. Then, the condition i <= 5 is evaluated. Since i is less than or equal to 5, the condition is true, and the loop continues. This process repeats until i becomes 6, at which point the condition i <= 5 becomes false, and the loop exits.

The output of the example will be:

1

2

3

4

5

The do-while loop is useful when you want to ensure that the code block is executed at least once, regardless of the condition. After the first iteration, the loop continues executing as long as the condition remains true.