下面的程序很简单，但为什么就是没有输入tomoeeow，我纳闷！请有经验人士指教！

#include<stdio.h>
main()
{
   char a[80]="tomoeeow",b[80]="",c[80]="";
   FILE *fp=NULL,*fq=NULL;

   fp=fopen("a.txt","r+");
   if(fp==NULL)  { printf("can't open this file\n ");  exit(0); }
   fprintf(fp,"%s",a);
   fgets(fp,"%s",b);
   fq=fopen("c.txt","r+");
   if(fq==NULL) {  printf("can't open this file\n ");  exit(0); }
   fprintf(fq,"%s",b);
   fgets(fq,"%s",c);
   puts(c);
   fclose(fp);
   fclose(fq);
}

#include <unistd.h>
#include<stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char* argv[])
{
   char a[80]="tomoeeow",b[80],c[80];
   FILE *fp=NULL,*fq=NULL;
 
   memset(b, '\0', 80);
   memset(c, '\0', 80);   

   fp=fopen("a.txt","r+");
   if(fp==NULL)  {
      
       printf("can't open this file\n ");  
       exit(0);
   }
   
   fprintf(fp,"%s",a);
   rewind(fp);
   fread(b, 20, 1, fp);
   fclose(fp);
   printf("1=====%s\n", b);  
   
   fq=fopen("c.txt","r+");
   if(fq==NULL) {  
      
       printf("can't open this file\n ");  
       exit(0);
   }
   fprintf(fq,"%s",b);
   fread(c, 20, 1, fq);
      
   //puts(c);  //你对puts用法有点误解吧！用法如下：puts() writes the string s and a trailing newline to stdout.

   fclose(fq);
   printf("2=====%s\n", b);  
      
   return 0;
   
}

fgets(str, n, fp)这是书上的，你的fgets(fp, %s, b);这样用是不是错了？

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
   char a[80]="tomoeeow",b[80],c[80];
   FILE *fp=NULL,*fq=NULL;

   fp=fopen("a.txt","w");
   if(fp==NULL)  { printf("can't open this file\n ");  exit(0); }
   fprintf(fp,"%s",a);
   fclose(fp);
   fp=fopen("a.txt","r");
   fgets(b, 20, fp);
   fclose(fp);
   fq=fopen("c.txt","w");
   if(fq==NULL) {  printf("can't open this file\n ");  exit(0); }
   fprintf(fq,"%s",b);
   fclose(fp);
   fq=fopen("c.txt","r");
   fgets(c, 20, fq);
   puts(c);
   fclose(fp);

  system("PAUSE");   
  return 0;
}
我按你的方式改了一下可以运行了。不知道是不是你要的结果  我也是新手 一起学习哦