Summary  
This chapter explains the do-while loop, a control flow structure that executes its code block once before evaluating its condition and then repeats the block while the condition remains true.  

General domain of usage  
User input validation and prompting until valid data is provided.

Let's consider the **do-while** loop. This loop is similar to the **while** loop but has a key distinction.

# Syntax
The **do-while** loop begins with the `do` keyword, encloses the code block within curly braces `{}`, and concludes with the `while` keyword followed by the condition in parentheses `()` without the need for an additional code block:
```js
do {
  // code block
} while (condition);
```
Here's an example:

let a = 0;

do {
  console.log(a);
  a++;
} while (a <= 3 && a >= 1);

At the outset, the variable `a` was initialized to `0`, and the condition `a >= 1` was evaluated after the `a++` operation.

The code block within the `do` is guaranteed to be executed at least once:

// `while` loop
while (false) {
  console.log("while"); // Not executed
}

// `do-while` loop
do {
  console.log("do-while"); // Executed 1 time
} while (false);

The **do-while loop** is particularly useful when you need to prompt the user for input at least once and continue until the user enters valid data or meets a specific condition.

How many times will the following code print `"Invalid PIN"` to the console?

Learn the fundamentals of JavaScript, the backbone of dynamic web development. Discover essential concepts like syntax, variables, data types, and operators. Explore how to use conditional statements, loops, and functions to create interactive and efficient programs. Master the building blocks of JavaScript and lay the groundwork for more advanced programming skills.

Discover the fundamentals of JavaScript, including its purpose and syntax. Learn how to work with the console for output and use comments to organize and document your code. These foundational skills will prepare you for a deeper exploration of JavaScript's capabilities.

Explore the building blocks of JavaScript by distinguishing between literals and variables. Understand the core data types, including `null` and arrays, and learn how to manipulate them using array methods.

Learn how to manipulate JavaScript's data types through essential operations. Master assignment, mathematical operations, incrementing and decrementing, comparisons, logical operations, and string concatenation.

Discover how to control the flow of your programs with conditional statements. Master `if`, `else`, and `else if` to instruct JavaScript on making decisions and executing code based on different conditions.

Streamline your code by mastering JavaScript's looping structures. Explore `while`, `do while`, and `for` loops, and learn how to control their behavior using `break` and `continue`. Unlock the power of loops to perform repetitive tasks efficiently.

Discover the power of functions in JavaScript. Learn how to define functions, work with arguments, and use the `return` statement to create reusable and efficient code. Mastering functions will enhance your ability to write clean and modular programs.

Using the do while Loop for Iteration

Syntax

Awesome!

Using the do while Loop for Iteration

Syntax