无尽的while循环 - C编程

Question

我试图创建一个程序来比较两个文件，并检查第一个文件中是否存在第二个文件。 函数r_scan进入无限循环。 有人知道为什么它不工作？

这是我的代码：

/** 
    The function scan the file and check if there is a virus in the file. 

    Input: 
    virus_address - The address of the virus file. 
    scaned_address - The adress of the file that we scan. 
    Output: 
    end - If the the file infected. 0 - infected, 1 - not infected. 
    **/ 

    int r_scan(char* virus_address, char* scaned_address) 
    { 
     //INIT 
     char v = ' ', s = ' '; 
     int end = 1, i = 0; 
     long seek = 0; 
     FILE* vp = NULL; 
     FILE* sp = NULL; 
     //Open th5e files. 
     vp = fopen(virus_address, "rb"); 
     sp = fopen(scaned_address, "rb"); 
     fseek(vp, 0, SEEK_SET); 
     fseek(sp, 0, SEEK_SET); 
     //pre scanning 
     seek = 0; 
     //Check if the file infected. 
     while (!(feof(sp)) && end) 
     {   
      fread(&s, 1, 1, sp); 

      if (v == s) 
      { 
       v = fgetc(vp); 
      } 
      else 
      { 
       seek++; 
       fseek(vp, 0, SEEK_SET); 
       fseek(sp, seek, SEEK_SET); 
       fread(&v, 1, 1, vp); 
      } 
      if (v == EOF) 
      { 
       end = 0; 
      } 
     } 
    fclose(vp); 
    fclose(sp); 
    return end; 
} 

Answer 1

的fseek手册页说：

成功调用FSEEK（）函数清除档案结尾指标

当程序循环时，在feof(sp)之前调用fseek(sp, seek, SEEK_SET);，这就是为什么feof始终返回0。而且因为你没有测试返回值fread(&s, 1, 1, sp);你的程序永远循环。