27.读文件时通过两种方式判断文件结尾

//判断读到文件末尾
#include <stdio.h>
#define F_PRINT_ERR(e)\
do\
{\
    if(e == NULL)\
    {\
      printf("open error");\
      exit(-1);\
    }\
}\
while(0)
int main(int argc,char* argv[])
{

    FILE* pf = fopen("G:/qtcode/pfw.txt","w+");
    F_PRINT_ERR(pf);
//往文件里写几个字符进去
    char ch;
    for(ch = 'a';ch <= 'd';ch++)
    {
        putchar(fputc(ch,pf));
    }
    putchar(10);
    rewind(pf);
//尝试通过两种方式判断读到文件末尾
#if 0
    //错误用法
    while(!feof(pf))//
    {
        ch = fgetc(pf);
        printf("%x->%c\n",ch,ch);
    }
#endif

#if 0
    //正确用法，先读再判断
    while((ch = fgetc(pf)) && (!feof(pf)))
    {
        printf("%x->%c\n",ch,ch);
    }
#endif

#if 0
    //正确用法，先读再判断
    ch = fgetc(pf);
    while(!feof(pf))
    {
        printf("%x->%c\n",ch,ch);
        ch = fgetc(pf);
    }
#endif

#if 1
    while((ch = fgetc(pf)) != EOF)
    {
        printf("%x->%c\n",ch,ch);
    }
#endif

    return 0;
}