What are the loop structures in javascript?

There are three loop structures in JavaScript: for loop: repeatedly executes a block of code under given conditions for a known number of iterations. while loop: As long as the condition is true, the code block is executed repeatedly, used to perform iteration when the condition is met. do-while loop: Execute a block of code at least once, then check a condition and repeat the block of code as long as the condition is true.

Loop Structure in JavaScript

In JavaScript, the loop structure allows us to repeat a block of code a specified number of times . There are three main loop structures in JavaScript:

1. for loop

The for loop uses the following syntax:

<code>for (let i = 0; i < n; i++) {
  // 代码块
}</code>

• let i = 0: Declare a variable i and initialize it to 0.
• i < n: Loop condition, the loop will continue when i is less than n.
• i : After each iteration, i will be incremented by 1.

2. while loop

while loop uses the following syntax:

<code>while (condition) {
  // 代码块
}</code>

• condition: loop condition, the loop will continue as long as the condition is true.

3. do-while loop

The do-while loop is similar to the while loop, but the code block is executed before the condition is checked. Its syntax is as follows:

<code>do {
  // 代码块
} while (condition);</code>

• condition: Loop condition, the loop will end when the condition is false.

Example

for loop:Print numbers 1 to 10

<code class="javascript">for (let i = 1; i <= 10; i++) {
  console.log(i);
}</code>

while loop:Print a random number until it is greater than 5

<code class="javascript">let randomNumber = Math.random();
while (randomNumber <= 0.5) {
  randomNumber = Math.random();
}
console.log(randomNumber);</code>

do-while loop: Print the numbers 1 to 3 at least once

<code class="javascript">let i = 0;
do {
  i++;
  console.log(i);
} while (i < 3);</code>

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