for Loop
The for loop is perfect when you know the number of iterations in advance. It has three parts: initialiser, condition, and iterator—all optional.
for loop examples
ForLoop.cs
// Count up
for (int i = 0; i < 5; i++)
Console.Write(i + " "); // 0 1 2 3 4
Console.WriteLine();
// Count down
for (int i = 10; i >= 1; i--)
Console.Write(i + " "); // 10 9 8 ... 1
Console.WriteLine();
// Multiplication table
for (int r = 1; r <= 3; r++)
for (int c = 1; c <= 3; c++)
Console.Write($"{r*c,4}");while & do-while Loops
Use while when the number of iterations is unknown and you want to check the condition before the first iteration. Use do-while to guarantee at least one execution.
while examples
While.cs
// while — reads until user types 'quit'
string input = "";
while (input != "quit")
{
Console.Write("Enter command: ");
input = Console.ReadLine() ?? "";
}
// do-while — menu loop
int choice;
do
{
Console.WriteLine("1. Start 2. Settings 3. Exit");
choice = int.Parse(Console.ReadLine() ?? "0");
} while (choice != 3);foreach Loop
The foreach loop iterates over any IEnumerable collection—arrays, lists, strings, and more. The loop variable is read-only; you cannot assign to it inside the loop.
foreach examples
ForEach.cs
string[] fruits = { "apple", "banana", "cherry" };
foreach (string fruit in fruits)
Console.WriteLine(fruit.ToUpper());
// foreach over a string (iterates characters)
foreach (char c in "Hello")
Console.Write(c + "-"); // H-e-l-l-o-break & continue
break exits the loop immediately. continue skips the rest of the current iteration and jumps to the next.
break and continue
BreakContinue.cs
for (int i = 0; i < 10; i++)
{
if (i == 3) continue; // skip 3
if (i == 7) break; // stop at 7
Console.Write(i + " "); // 0 1 2 4 5 6
}