第五篇--VS2017如何生成Dll文件

#pragma once
#ifdef DLL_TraiNING_API
#else                                                                            
#define DLL_TraiNING_API _declspec(dllimport) //当编译时，头文件不参加编译，所以.cpp文件中先定义，后头文件被包含进来，因此外部使用时，为dllexport，而在内部编译时，则为dllimport
#endif  

class DLL_TraiNING_API arithmetic_operation              //需要被外界调用的类（父类）
{
public:
    double Add(double a,double b);
    double Sub(double a,double b);
    double Multi(double a,double b);
    double Div(double a,double b);
};

int DLL_TraiNING_API export333();

// selfTrainingDll.cpp : Defines the exported functions for the DLL application.
//

#include "stdafx.h"

#define DLL_TraiNING_API _declspec(dllexport)

#include <iostream>
#include "selfTrainingDll.h"
using namespace std;

double DLL_TraiNING_API arithmetic_operation::Add(double a,double b) {
    return a+b;
}

double DLL_TraiNING_API arithmetic_operation::Sub(double a,double b) {
    return a - b;
}

double DLL_TraiNING_API arithmetic_operation::Multi(double a,double b) {
    return a * b;
}

double DLL_TraiNING_API arithmetic_operation::Div(double a,double b) {
    return a / b;
}

int DLL_TraiNING_API export333() {
    return 333;
}

// UseSelfDll.cpp : This file contains the ‘main‘ function. Program execution begins and ends there.
//

#include "pch.h"
#include <iostream>

using namespace std;

#include "selfTrainingDll.h"
#pragma comment(lib,"selfTrainingDll.lib")

int main()
{
    arithmetic_operation ao;
    cout << ao.Add(1,2) << endl;
    cout << ao.Sub(2,1) << endl;
    cout << ao.Multi(2,1) << endl;
    cout << ao.Div(6,4) << endl;
    cout << export333() << endl;
    cout << "Hello World!\n"; 
}