Lernen While Loops in Action | While and Do-While Loops: Control and Flexibility

When you need to repeat an action an unknown number of times, or continue looping until a specific condition is met, a while loop is your tool of choice. The syntax of a while loop in C# is straightforward: you write the keyword while, followed by a condition in parentheses, and then a block of code in curly braces.

while (condition)
{
    // code to execute
}

The loop will keep running as long as the condition evaluates to true. Unlike a for loop, which is ideal when you know exactly how many times you want to repeat something, a while loop is better suited for situations where the number of iterations is not predetermined. This makes while loops especially useful for indefinite iteration and condition-based control.

Program.cs


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namespace ConsoleApp
{
    public class Program
    {
        public static void Main()
        {
            int number = 1;
            while (number <= 5)
            {
                System.Console.WriteLine(number);
                number++;
            }
        }
    }
}

In the example above, the loop starts with number set to 1 and continues as long as number is less than or equal to 5. Each time through the loop, the value of number is printed and then incremented. The key to a well-behaved while loop is the loop condition—the expression inside the parentheses. This condition is checked before each iteration. If it is true, the loop body runs; if false, the loop stops. It is crucial to update any variables involved in the condition inside the loop body. If you forget to update the loop variable, the condition may never become false, causing an infinite loop that never ends.

Program.cs


              123456789101112131415
            
namespace ConsoleApp
{
    public class Program
    {
        public static void Main()
        {
            int value = 2;
            while (value <= 100)
            {
                System.Console.WriteLine(value);
                value = value * 2;
            }
        }
    }
}

While loops are especially useful in real-world scenarios where you must wait for a particular condition to be met. For instance, you might use a while loop to wait for a user to enter valid input, monitor a process until it completes, or repeatedly check for a resource to become available. These cases share a common characteristic: you do not know in advance how many times you will need to repeat the check, so a while loop gives you the flexibility to keep going until you get the result you need.

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Abschnitt 2. Kapitel 1

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while (condition)
{
    // code to execute
}

Program.cs


              123456789101112131415
            
namespace ConsoleApp
{
    public class Program
    {
        public static void Main()
        {
            int number = 1;
            while (number <= 5)
            {
                System.Console.WriteLine(number);
                number++;
            }
        }
    }
}

Program.cs


              123456789101112131415
            
namespace ConsoleApp
{
    public class Program
    {
        public static void Main()
        {
            int value = 2;
            while (value <= 100)
            {
                System.Console.WriteLine(value);
                value = value * 2;
            }
        }
    }
}

War alles klar?

Danke für Ihr Feedback!

Abschnitt 2. Kapitel 1

While Loops in Action

1. What happens if the loop variable in a while loop is never updated?

2. Which scenario is best suited for a while loop instead of a for loop?

3. How does a while loop differ from a for loop in terms of initialization and increment?

Awesome!

While Loops in Action

1. What happens if the loop variable in a while loop is never updated?

2. Which scenario is best suited for a while loop instead of a for loop?

3. How does a while loop differ from a for loop in terms of initialization and increment?