Mastering Loops in C#: for, while, do-while, and foreach

Loops allow your C# programs to repeat tasks efficiently — without writing the same code over and over again. Whether you’re counting numbers, processing lists, or repeating user input prompts, loops are a vital tool in every C# developer’s toolkit.

Here, we’ll explore the four main loop types in C# — for, while, do-while, and foreach — with clear examples and tips on when to use each one.

🎯 Why Use Loops?

Loops help you:

• Repeat a block of code a set number of times
• Iterate over items in arrays or collections
• Automate repetitive tasks like input, calculations, or output

🔁 The for Loop

Use a for loop when you know exactly how many times you want to repeat something.

🔹 Syntax:

for (initialization; condition; update)
{
    // Code to repeat
}

🔸 Example:

for (int i = 1; i <= 5; i++)
{
    Console.WriteLine("Count: " + i);
}

✅ Use for when working with counters or index-based operations.

🔄 The while Loop

A while loop checks the condition before each iteration. It repeats as long as the condition is true.

🔹 Syntax:

while (condition)
{
    // Code to repeat
}

🔸 Example:

int count = 0;

while (count < 3)
{
    Console.WriteLine("Repeating...");
    count++;
}

⚠️ Be careful of infinite loops — always make sure the condition can eventually become false.

🔁 The do-while Loop

A do-while loop runs the code at least once, then checks the condition.

🔹 Syntax:

do
{
    // Code to repeat
}
while (condition);

🔸 Example:

string input;

do
{
    Console.Write("Enter your name: ");
    input = Console.ReadLine();
}
while (input == "");

✅ Use do-while when you want to run the loop body at least once (e.g., menu prompts, user input).

🔁 The foreach Loop

Use foreach to loop over items in arrays, lists, or other collections. It’s simple and avoids index errors.

🔹 Syntax:

foreach (var item in collection)
{
    // Code using item
}

🔸 Example:

string[] fruits = { "Apple", "Banana", "Cherry" };

foreach (string fruit in fruits)
{
    Console.WriteLine(fruit);
}

✅ Use foreach when you don’t need to modify the collection or track indexes.

🧪 Quick Challenge: Combine Loops

Try writing a program that:

• Uses a for loop to ask the user for 5 numbers
• Adds them up in a total
• Then uses a foreach loop to print all the numbers back

int[] numbers = new int[5];

for (int i = 0; i < numbers.Length; i++)
{
    Console.Write("Enter number " + (i + 1) + ": ");
    numbers[i] = int.Parse(Console.ReadLine());
}

Console.WriteLine("\nYou entered:");
foreach (int number in numbers)
{
    Console.WriteLine(number);
}

🧠 Summary: When to Use Each Loop

🚀 Need Help?

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