编辑代码

using System;

public class HelloWorld
{
    // 定义委托
    delegate int Transformer (int x);

    static int Square (int x) { 
        int result = x * x;
        Console.WriteLine($"The result of Square is {result}");
        return result; 
    }
    static int Cube (int x) { 
        int result = x * x * x;
        Console.WriteLine($"The result of Cube is {result}");
        return result; 
    }

    public static void Main()
    {
       Transformer t = Square;
       Console.WriteLine($"The result of transformer is {t(3)}");

       t = Cube;
       Console.WriteLine($"The result of transformer is {t(3)}");

       t += Square;
       t(3);

    }
}