在C#中调用C++库

// C++ 库
#include<iostream>

extern "C" __declspec(dllexport) int add(int a, int b) {
    return a + b;
}

// C# 代码
using System;
using System.Runtime.InteropServices;

class Program {
    [DllImport("CppLibrary.dll", CallingConvention = CallingConvention.Cdecl)]
    public static extern int add(int a, int b);

    static void Main(string[] args) {
        int result = add(1, 2);
        Console.WriteLine("The result is: " + result);
    }
}