#include "stdio.h"
#include "conio.h"
#include "math.h"
#include "string.h"
main()

{char a[]="abcd hgh s1&&&",ch;
int i=0,j=0,k=0,l=0;
FILE *fp;
fp=fopen("d:\\liangnv.txt","w");
fputs(a,fp);

fclose(fp);
fp=fopen("d:\\liangnv.txt","r");
ch=fgetc(fp);
while(ch!=EOF)
{ if(ch>='a'&&ch<='z')i++;
else if(ch>='A'&&ch<='Z')j++;
else if(ch>='1'&&ch<='9')k++;
else l++;

ch=fgetc(fp);}
fclose(fp);
printf("小写字母%d\n",i);
printf("大写字母%d\n",j);
printf("数字\n%d\n",k);
printf("字符%d\n",l);
getch();
}

while(!feof(fp))

或者在前面加上“#define EOF     (-1)”即可。
TC没有定义这个常量？