C++ Primer对于分离式编译的介绍很简单，于是自己想试一下怎么使用。按照以下代码运行，在main函数中运行fun()和absolute()时会提示没有定义函数。请问这是为什么？应该怎样做才能让代码顺利运行？

主函数：

#include  #include  #include  #include "Chapter6.h" using namespace std; //cnt函数每次被调用则返回值+1 int cnt() { static int rtn = 0; return rtn++; } int main() { for (size_t i = 0; i < 10; ++i) { cout << cnt() << endl; } int a = 0; string c; do { cout << "Please enter a number:" << endl; cin >> a; cout << a << "! = " << fun(a) << '\n' << absolute(a) << endl; //undefined reference to 'absolute(double), 'fun(int)' cout << "More numbers? Please enter yes or no." << endl; cin >> c; } while (!c.empty() && c[0] == 'y'); return 0; }

Chapter6.h头文件：

#include  #include  #include  using namespace std; int fun(int a); double absolute(double a); int cnt();

fact.cpp：

#include  #include  #include  #include "Chapter6.h" using namespace std; //阶乘计算 int fun(int a) { int rec = 1; while (a > 1) { rec *= a--; } return rec; } //返回绝对值 double absolute(double a) { if (a >= 0) return a; else return -a; }