안녕하세요 링크에러가 나서요
초보인데요
myfun.h=====================================
#include <stdio.h>

void sum();
void mul();


extern int i, j;
extern int x, y;
extern int res;

sample1.c==================================
#include <stdio.h>
#include "myfun.h"

int res;

void main()
{
  
   sum();
}

sample2.c================================
#include "myfun.h"

int i=10, j=10;

void sum()
{
  
   res = i + j;

   printf("res = i + j ==> %d\n", res);
   mul();

}

  
sample3.c================================
#include "myfun.h"

int x=20, y=20;

void mul()
{

  res =  x * y;

  printf("res = i * j ==> %d\n", res);
}


컴파일은 되는데 링크에러가 다음과 같이 나옵니다
Linking...
LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16
Terran.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

해결좀 해주세요