C语言尝试在不同源文件中调用程序段

基于Visual Studio 2015

将下面两个cpp文件置于同一源文件目录下即可

源.cpp

#include <stdio.h>
int main()
{
    extern int sum(int x, int y);
    int x, y;
    printf("please enter two nums:");
    scanf("%d%d", &x, &y);
    printf("sum:%d\n", sum(x, y));
    return ;
}

add.cpp

int sum(int x, int y)
{
    return x + y;
}

运行结果如下：