C#: طريقة متقدمة

using System;

class Calculator
{
    public int Add(int a, int b)
    {
        return a + b;
    }

    public double Add(double a, double b)
    {
        return a + b;
    }

    public int Add(int a, int b, int c)
    {
        return a + b + c;
    }
}

class Program
{
    static void Main()
    {
        Calculator calc = new Calculator();
        Console.WriteLine(calc.Add(1, 2));
        Console.WriteLine(calc.Add(1.5, 2.5));
        Console.WriteLine(calc.Add(1, 2, 3));
    }
}

3
4
6

using System;

class Program
{
    static void Print(string msg, int count = 1, string prefix = "")
    {
        for (int i = 0; i < count; i++)
        {
            Console.WriteLine($"{prefix}{msg}");
        }
    }

    static void Main()
    {
        Print("Hello");
        Print("Hi", 3);
        Print(msg: "World", prefix: "> ");
        Print(prefix: ">> ", count: 2, msg: "Test");
    }
}

Hello
Hi
Hi
Hi
> World
>> Test
>> Test

using System;

class Program
{
    static void Swap(ref int a, ref int b)
    {
        int temp = a;
        a = b;
        b = temp;
    }

    static void Main()
    {
        int x = 10;
        int y = 20;
        Console.WriteLine($"Before: x={x}, y={y}");
        Swap(ref x, ref y);
        Console.WriteLine($"After: x={x}, y={y}");
    }
}

Before: x=10, y=20
After: x=20, y=10

using System;

class Program
{
    static bool TryParseInt(string s, out int result)
    {
        result = 0;
        foreach (char c in s)
        {
            if (c < '0' || c > '9')
                return false;
            result = result * 10 + (c - '0');
        }
        return true;
    }

    static void Main()
    {
        if (TryParseInt("123", out int number))
        {
            Console.WriteLine($"Parsed: {number}");
        }

        if (!TryParseInt("abc", out int fail))
        {
            Console.WriteLine("Parse failed");
        }
    }
}

Parsed: 123
Parse failed

using System;

struct BigData
{
    public long A, B, C, D, E, F, G, H;
}

class Program
{
    static void Process(in BigData data)
    {
        Console.WriteLine($"A={data.A}, B={data.B}");
    }

    static void Main()
    {
        BigData d = new BigData { A = 100, B = 200 };
        Process(in d);
        Process(d);
    }
}

A=100, B=200
A=100, B=200

using System;

class Program
{
    static int Sum(params int[] numbers)
    {
        int total = 0;
        foreach (int n in numbers)
        {
            total += n;
        }
        return total;
    }

    static void Main()
    {
        Console.WriteLine(Sum(1, 2, 3));
        Console.WriteLine(Sum(10, 20, 30, 40, 50));
        Console.WriteLine(Sum());
    }
}

6
150
0

using System;

class Program
{
    static long Factorial(int n)
    {
        if (n <= 1)
            return 1;
        return n * Factorial(n - 1);
    }

    static void Main()
    {
        for (int i = 1; i <= 10; i++)
        {
            Console.WriteLine($"{i}! = {Factorial(i)}");
        }
    }
}

1! = 1
2! = 2
3! = 6
4! = 24
5! = 120
6! = 720
7! = 5040
8! = 40320
9! = 362880
10! = 3628800

using System;

class Program
{
    static int Fibonacci(int n)
    {
        if (n <= 0) return 0;
        if (n == 1) return 1;
        return Fibonacci(n - 1) + Fibonacci(n - 2);
    }

    static void Main()
    {
        for (int i = 0; i <= 10; i++)
        {
            Console.Write($"{Fibonacci(i)} ");
        }
        Console.WriteLine();
    }
}

0 1 1 2 3 5 8 13 21 34 55

using System;

class Program
{
    static int[] GetEvenSquares(int[] numbers)
    {
        bool IsEven(int n) => n % 2 == 0;
        int Square(int n) => n * n;

        System.Collections.Generic.List```<int>``` result = new System.Collections.Generic.List```<int>```();
        foreach (int n in numbers)
        {
            if (IsEven(n))
            {
                result.Add(Square(n));
            }
        }
        return result.ToArray();
    }

    static void Main()
    {
        int[] data = { 1, 2, 3, 4, 5, 6, 7, 8 };
        int[] result = GetEvenSquares(data);
        Console.WriteLine(string.Join(", ", result));
    }
}

4, 16, 36, 64

using System;

class ScopeDemo
{
    int classField = 100;

    void MethodA()
    {
        int localVar = 10;
        Console.WriteLine($"classField={classField}, localVar={localVar}");

        if (true)
        {
            int blockVar = 20;
            Console.WriteLine($"blockVar={blockVar}");
        }
    }

    void MethodB()
    {
        Console.WriteLine($"classField={classField}");
    }
}

class Program
{
    static void Main()
    {
        ScopeDemo demo = new ScopeDemo();
        demo.MethodA();
        demo.MethodB();
    }
}

classField=100, localVar=10
blockVar=20
classField=100