C/C++实现文件自校验代码

#include <iostream>
#include <stdio.h>
extern long FileSizeof(char *);
int main()
{
  if(FileSizeof("\\a.exe")==20499)    #指定文件大小
  {
    std::cout<<"没有被破解"<<std::endl;
    getchar();
  }else
  {
    std::cout<<"已经被破解"<<std::endl;
    getchar();
  }
  return 0;
}

extern long FileSizeof(char FileName)
{
    FILE
fop;
    
long temp;
    fop
=fopen(FileName,r);
    fseek(fop,
0,SEEK_END);
    temp
=ftell(fop);
    fclose(fop);
    
return temp;
}