লুপস (Loops)

// for loop — "do this N times"
// (start; keep going while; after each loop)
Console.WriteLine("Countdown:");
for (int i = 5; i >= 1; i--)
{
    Console.Write($"{i}... ");
}
Console.WriteLine("Liftoff!");

// while loop — "keep going until this is false"
int fuel = 100;
Console.WriteLine("\nBurning fuel:");
while (fuel > 0)
{
    fuel -= 30;
    Console.WriteLine($"  Fuel remaining: {Math.Max(fuel, 0)}%");
}

// do-while — runs AT LEAST once
int attempts = 0;
do
{
    attempts++;
    Console.WriteLine($"Attempt #{attempts}");
} while (attempts < 3);

Countdown:
5... 4... 3... 2... 1... Liftoff!

Burning fuel:
  Fuel remaining: 70%
  Fuel remaining: 40%
  Fuel remaining: 10%
  Fuel remaining: 0%
Attempt #1
Attempt #2
Attempt #3

// foreach with an array
string[] heroes = { "Spider-Man", "Batman", "Wonder Woman", "Iron Man" };
foreach (string hero in heroes)
{
    Console.WriteLine($"  Hero: {hero}");
}

// foreach with a string (each char!)
string word = "C#";
foreach (char c in word)
{
    Console.Write($"[{c}]");
}
Console.WriteLine();

// break — emergency exit
Console.WriteLine("\nSearching for Batman:");
foreach (string hero in heroes)
{
    if (hero == "Batman")
    {
        Console.WriteLine("  Found him!");
        break;  // stop the loop right now
    }
    Console.WriteLine($"  Not {hero}...");
}

// continue — skip this one, keep going
Console.WriteLine("\nOdd numbers only:");
for (int i = 1; i <= 10; i++)
{
    if (i % 2 == 0)
        continue;  // skip even numbers
    Console.Write($"{i} ");
}
Console.WriteLine();

  Hero: Spider-Man
  Hero: Batman
  Hero: Wonder Woman
  Hero: Iron Man
[C][#]

Searching for Batman:
  Not Spider-Man...
  Found him!

Odd numbers only:
1 3 5 7 9 

// Print a multiplication table
Console.WriteLine("Multiplication Table (1-4):");
for (int row = 1; row <= 4; row++)
{
    for (int col = 1; col <= 4; col++)
    {
        Console.Write($"{row * col,4}"); // ,4 pads to 4 chars
    }
    Console.WriteLine();
}

// Build a triangle
Console.WriteLine("\nTriangle:");
for (int i = 1; i <= 5; i++)
{
    Console.WriteLine(new string('*', i));
}

Multiplication Table (1-4):
   1   2   3   4
   2   4   6   8
   3   6   9  12
   4   8  12  16

Triangle:
*
**
***
****
*****