c++ - Visual Studio C++ 项目 Linker2019 错误

Question

我有一个包含以下文件的简单项目，但无法运行。

乘法.h

class Multiplication{
public:
float multiply(float x, float y);
};

减法.h

class Subtraction{
public:
float subtract(float x, float y);
};

乘法.cpp

#include "multiplication.h"

float Multiplication::multiply(float x, float y){
float prod;
prod = x*y;
return prod;
};

减法.cpp

#include "subtraction.h"

float Subtraction::subtract(float x, float y){
float diff;
diff = x-y;
return diff;
};

主文件

#include "subtraction.h"
#include "multiplication.h"
#include <iostream>

int main(){
//lets calculate 4*5-20
Multiplication* m = new Multiplication();
Subtraction* s = new Subtraction();
std::cout<<s->subtract(m->multiply(4,5),20);
}

但是，当我尝试构建项目时遇到以下错误并且无法弄清楚原因，希望得到一些帮助:)

标签： c++visual-studio