What are undeclared and undefined variables? in JavaScript with code example

 Sure, I can provide you with a guide on JavaScript loops with code examples.

Loops in JavaScript are used to execute a block of code repeatedly until a specific condition is met. There are three types of loops in JavaScript:

1. for loop
2. while loop
3. do-while loop

1. for loop

The for loop is used to iterate over a block of code a fixed number of times. It has the following syntax:

css
for (initialization; condition; increment) {
  // code to be executed
}

The initialization expression is executed once before the loop starts. The condition expression is evaluated before each iteration, and if it is true, the loop continues. The increment expression is executed after each iteration.

Here's an example of a for loop that iterates from 0 to 4:

css
for (let i = 0; i < 5; i++) {
  console.log(i);
}

Output:

0
1
2
3
4

2. while loop

The while loop is used to iterate over a block of code as long as a condition is true. It has the following syntax:

arduino
while (condition) {
  // code to be executed
}

The condition expression is evaluated before each iteration, and if it is true, the loop continues.

Here's an example of a while loop that iterates until the variable i is less than 5:

css
let i = 0;

while (i < 5) {
  console.log(i);
  i++;
}

Output:

0
1
2
3
4

3. do-while loop

The do-while loop is similar to the while loop, but the code inside the loop is executed at least once before the condition is checked. It has the following syntax:

arduino
do {
  // code to be executed
} while (condition);

The condition expression is evaluated after each iteration, and if it is true, the loop continues.

Here's an example of a do-while loop that iterates until the variable i is less than 5:

css
let i = 0;

do {
  console.log(i);
  i++;
} while (i < 5);

Output:

0
1
2
3
4

I hope this guide helps you understand JavaScript loops better!