**OCaml**, also known as **Objective Caml**, is a high-level general-purpose programming language. It is a combination of [functional](https://www.educative.io/answers/what-is-functional-programming) and #key# imperative: In imperative programming, functions contain explicit instructions detailing each step needed to solve a problem. #key# programming. Ocaml is known for its strong type system, #key# type inference: Automatic detection of the type of an expression in a formal language #key#, and support for functional programming concepts. 

In this Answer, we will discuss the OCaml `while` loop in detail.

# The `while` loop

A `while` loop executes a code block until a condition is true. The `while` loop condition is checked before executing the defined code block. When we enter a `while` loop, the defined condition is checked. If the condition is true, then the code block is executed. Otherwise, the `while` loop breaks if the condition is evaluated as false.

The illustration below shows that the condition is checked before executing the code block when we enter the `while` loop. If the condition is false, the `while` loop breaks, and the code block is not executed. In the case of a true condition, the code will execute and check the `while` condition again for the next iteration. This process continues until the condition becomes false.





## Syntax

The syntax of the `while` loop is given below: 

while condition do
  # Execute Code block
done

ocaml

It checks the `condition` and then goes through the loop’s body based on whether it is true or false.

## Code example

Let's go through an example of a `while` loop in OCaml where we have to print numbers from $1$ to $10$.

let current_number = ref 1 in
while !current_number <= 10 do
  print_string "The number is: ";
  print_int !current_number;
  print_newline ();
  current_number := !current_number + 1
done;;

## Code explanation

In the code above:

- **Line 1:** The code defines a reference variable, `current_number`, to check the condition of the loop.

- **Line 2:** The code goes through the `condition` of the loop and checks if `current_number <= 10`.

- **Lines 3--5:** The code prints the `current_number` and new line.

- **Line 6:** The code updates the value of `current_number` by `1`.

- **Line 7:** The statement `done` shows that the `while` loop ends here.

ocaml.tar.gz

What is the OCaml while loop?

OCaml’s while loop repeatedly executes a code block as long as a specified condition remains true, checking the condition before each iteration.

What is the OCaml while loop?

The while loop

Syntax

Code example

Code explanation

The `while` loop