外部功能？

Question

Sample1.c

#include "stdio.h"
int f1(int x, int y)
{
  printf("%d %d", x, y);
  return x+y;
}

Sample2.c

#include "stdio.h"
extern int f1(int x,int y);
int main(void)
{
  printf(" %d\n", f1(5,6));
  return 0;
}

我试图在Turbo C/C++编译器(Windows XP)上编译该Sample1.c文件Sample2.c.它显示以下错误:

Compiling Sample2.c:
Linking Sample2.exe:
Linker Error : Undefined Symbol _f1 in module Sample2.c

有人可以帮我这方面吗？

Answer 1