DEV Community

Cover image for Day 5 of 30-Day .NET Challenge: While & do-while
Sukhpinder Singh
Sukhpinder Singh

Posted on • Originally published at singhsukhpinder.Medium

Day 5 of 30-Day .NET Challenge: While & do-while

Introduction

The do-while and while statements provide control over code execution flow by repeating a block of code until a condition is satisfied.

Learning Objectives

  • Utilize the do-while loop to iterate through a code block.

  • Implement the while loop to iterate through a code block as well.

Prerequisites for Developers

  • Familiarity with utilizing the if statement.

  • Proficiency in using foreach and for iteration statements.

  • Competence in writing Boolean expressions.

  • Knowledge of generating random numbers using the System.Random class and the Random.Next() method.

Getting Started

What is the do-while loop?

The do-while statement runs a statement or block of statements as long as a specified Boolean expression remains true. As this expression is evaluated after each loop execution, a do-while loop executes at least once.

Example: do-while

Let’s create code that continuously generates random numbers ranging from 1 to 10 until we generate the number 7. The number 7 could be generated in one iteration or after several iterations.

To begin, create a static class file called “WhileLoop.cs” within the console application. Insert the provided code snippet into this file.

/// <summary>
/// Outputs
/// 2
/// 5
/// 8
/// 2
/// 7
/// </summary>
public static void DoWhileLoopExample()
{
    Random random = new Random();
    int current = 0;

    do
    {
        current = random.Next(1, 11);
        Console.WriteLine(current);
    } while (current != 7);
}
Enter fullscreen mode Exit fullscreen mode

Execute the code from the main method as follows

#region Day 5 - While & do-while

WhileLoop.DoWhileLoopExample();

#endregion
Enter fullscreen mode Exit fullscreen mode

Console Output

2
5
8
2
7
Enter fullscreen mode Exit fullscreen mode

Example: while

The while statement will iterate based on the Boolean expression. To do that add another method into the same static class as shown below

/// <summary>
/// Outputs
/// 9
/// 7
/// 5
/// Last number: 1
/// </summary>
public static void WhileLoopExample()
{
    Random random = new Random();
    int current = random.Next(1, 11);

    while (current >= 3)
    {
        Console.WriteLine(current);
        current = random.Next(1, 11);
    }
    Console.WriteLine($"Last number: {current}");
}
Enter fullscreen mode Exit fullscreen mode

Execute the code from the main method as follows

#region Day 5 - While & do-while

WhileLoop.WhileLoopExample();

#endregion
Enter fullscreen mode Exit fullscreen mode

Console Output

9
7
5
Last number: 1
Enter fullscreen mode Exit fullscreen mode

Continue statement with do-while

Sometimes, developers need to skip the rest of the code within a code block and move on to the next iteration. To achieve this add another method into the same static class as shown below

    /// <summary>
    /// Outputs
    /// 5
    /// 1
    /// 6
    /// 7
    /// </summary>
    public static void ContinueDoWhileLoopExample()
    {
        Random random = new Random();
        int current = random.Next(1, 11);

        do
        {
            current = random.Next(1, 11);

            if (current >= 8) continue;

            Console.WriteLine(current);
        } while (current != 7);
    }
Enter fullscreen mode Exit fullscreen mode

Execute the code from the main method as follows

    #region Day 5 - While & do-while

    WhileLoop.ContinueDoWhileLoopExample();

    #endregion
Enter fullscreen mode Exit fullscreen mode

Console Output

    5
    1
    6
    7
Enter fullscreen mode Exit fullscreen mode

Complete Code on GitHub

GitHub — ssukhpinder/30DayChallenge.Net

C# Programming🚀

Thank you for being a part of the C# community! Before you leave:

If you’ve made it this far, please show your appreciation with a clap and follow the author! 👏️️

Follow us: X | LinkedIn | Dev.to | Hashnode | Newsletter | Tumblr

Visit our other platforms: GitHub | Instagram | Tiktok | Quora | Daily.dev

More content at C# Programming

Top comments (0)