কন্ডিশনালস (Conditionals)

int temperature = 28;

if (temperature > 35)
{
    Console.WriteLine("It's scorching! Stay indoors.");
}
else if (temperature > 25)
{
    Console.WriteLine("Nice and warm. Perfect for the beach!");
}
else if (temperature > 10)
{
    Console.WriteLine("A bit chilly. Grab a jacket.");
}
else
{
    Console.WriteLine("Freezing! Bundle up.");
}

// Nested if
int age = 16;
bool hasLicense = false;

if (age >= 16)
{
    if (hasLicense)
        Console.WriteLine("You can drive!");
    else
        Console.WriteLine("Old enough, but get your license first!");
}

Nice and warm. Perfect for the beach!
Old enough, but get your license first!

// Classic switch statement
string day = "Wednesday";
switch (day)
{
    case "Monday":
    case "Tuesday":
    case "Wednesday":
    case "Thursday":
    case "Friday":
        Console.WriteLine($"{day} is a weekday.");
        break;
    case "Saturday":
    case "Sunday":
        Console.WriteLine($"{day} is the weekend!");
        break;
    default:
        Console.WriteLine("Not a real day!");
        break;
}

// Modern switch expression (much cleaner!)
int score = 87;
string grade = score switch
{
    >= 90 => "A",
    >= 80 => "B",
    >= 70 => "C",
    >= 60 => "D",
    _     => "F"   // _ is the default/discard
};
Console.WriteLine($"Score {score} = Grade {grade}");

Wednesday is a weekday.
Score 87 = Grade B

// Pattern matching with types
object item = 3.14;
string description = item switch
{
    int n when n > 0    => $"Positive integer: {n}",
    int n               => $"Integer: {n}",
    double d            => $"Decimal number: {d}",
    string s            => $"Text: {s}",
    null                => "Nothing here!",
    _                   => "Something else entirely"
};
Console.WriteLine(description);

// Ternary operator — mini if/else
int hour = 14;
string period = hour < 12 ? "AM" : "PM";
Console.WriteLine($"It's {hour} — that's {period}");

// Nested ternary (use sparingly!)
string timeOfDay = hour < 12 ? "morning" : hour < 17 ? "afternoon" : "evening";
Console.WriteLine($"Good {timeOfDay}!");

Decimal number: 3.14
It's 14 — that's PM
Good afternoon!