using System;
using System.Linq.Expressions;
 
class Program
{
    static void Main(string[] args)
    {
        Console.WriteLine(Add(10, 20));
        Console.WriteLine(Add(10L, 20L));
        Console.WriteLine(Add(10.0, 20.0));
        Console.ReadKey();
    }
 
    static T Add<T>(T a, T b) where T : struct
    {
        var p1 = Expression.Parameter(typeof(T), "a");
        var p2 = Expression.Parameter(typeof(T), "b");
        var body = Expression.Add(p1, p2);
        var lambda = Expression.Lambda(body, new[] { p1, p2 });
        var compiled = (Func<T, T, T>)lambda.Compile();
        return compiled(a, b);
    }
}

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