多文件编译

C++

这个放在头文件
head.h

int Factorial(int);
int fun2();
int fun3(int n);

以下放在源文件
file1.cpp

#include<iostream>
using namespace std;
#include"head.h"
int Factorial(int n){
    if (n == 1)
        return 1;
    else return n *  Factorial(n - 1);
    }

file2.cpp

#include<iostream>
using namespace std;
#include"head.h"
int fun2(){
    int res = 0;
    res = (Factorial(5) + Factorial(7)) / 8;
    return res;
}

file3.cpp

#include<iostream>
using namespace std;
#include"head.h"
int fun3(int n){
    int res=0;
    for (int i = 1; i <= n; i++){
        res += Factorial(i);
    }
    return res;
}

mainf.cpp

#include<iostream>
using namespace std;
#include"head.h"
int main(){
    int n1 = fun2();
    cout <<"5！+7！的和除8的结果是："<< n1 << endl;
    int n2 = fun3(10);
    cout <<"1-10的阶乘的和是："<< n2 << endl;
    system("pause");
    return 0;
}

然后运行就好了