while and do-while Loops

Syntax

while (condition) {\n  // code\n}

Examples

int count = 0;

while (count < 5)
{
    Console.WriteLine(count);
    count++;
}

Console.WriteLine("Done");

int number;

do
{
    Console.Write("Enter a positive number: ");
    number = int.Parse(Console.ReadLine() ?? "0");
} while (number <= 0);

Console.WriteLine($"You entered: {number}");

int attempts = 0;

while (true)
{
    attempts++;
    if (attempts == 3)
    {
        Console.WriteLine($"Success after {attempts} attempts");
        break;
    }
}

Best practices

• Use a do-while loop specifically when the loop body must run at least once, such as showing a menu before checking for an exit condition
• Always ensure the while condition will eventually become false, or include a break, to avoid an infinite loop
• Prefer a for loop when the number of iterations is known in advance - reserve while for genuinely condition-driven repetition
• Double-check that variables used in the loop condition are actually being updated somewhere inside the loop body

At a glance

Purpose

Applications on the .NET platform

File extension

.cs

Runs in

.NET runtime

Usually used with

.NET SDK and libraries

Specifications & further reading

• C# language reference

Related C# documentation