Control Structures

Control structures allow modifying the execution flow of a program in C#.
With them, we can make decisions or repeat blocks of code based on conditions.

Decision Structures

- if (simple conditional)

Evaluates a condition and executes the block if it is true.

int age = 18;

if (age >= 18)
{
    Console.WriteLine("You are of legal age.");
}

---

- else

Adds an alternative block when the condition is false.

if (age >= 18)
{
    Console.WriteLine("You can enter.");
}
else
{
    Console.WriteLine("You cannot enter.");
}

- else if

int score = 85;

if (score >= 90)
{
    Console.WriteLine("Excellent");
}
else if (score >= 70)
{
    Console.WriteLine("Approved");
}
else
{
    Console.WriteLine("Failed");
}

- switch

Used when a variable can have multiple possible cases.

string day = "Monday";

switch (day)
{
    case "Monday":
        Console.WriteLine("Start of the week");
        break;
    case "Friday":
        Console.WriteLine("Weekend is near");
        break;
    default:
        Console.WriteLine("Normal day");
        break;
}

---

Loops

- for

Used when we know the exact number of iterations.

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

- foreach

Used to iterate over collections (lists, arrays, etc.).

string[] names = { "Ana", "Luis", "Pedro" };

foreach (string name in names)
{
    Console.WriteLine(name);
}

- while

Executes the block as long as the condition remains true.

int counter = 1;

while (counter <= 3)
{
    Console.WriteLine($"Counter: {counter}");
    counter++;
}

- do..while

Executes the block at least once, and then evaluates the condition.

int number = 1;

do
{
    Console.WriteLine($"Number: {number}");
    number++;
} while (number <= 3);