实例3：读写字节文件，每次读入一个缓存里面。

#include<stdio.h>

#include <stdlib.h>

#define MAXLEN 1024

int main()

{

   FILE *fpin ;

   FILE *fpout;

   unsigned char buf[MAXLEN];

   int c;

   fpout=fopen("c:\\dest.jpg","wb");

   if((fpin=fopen("c:\\test.jpg","rb"))!=NULL)

   {

      c = fread(buf,sizeof(unsigned char),MAXLEN,fpin);

      while(c!=0)

      {

         fwrite(buf,sizeof(unsigned char),c,fpout);

         c=fread(buf,sizeof(unsigned char),MAXLEN,fpin);

      }

   }

   else

   {

      printf("file not exist!");

      exit(1);

    }

    fclose(fpin);

    fclose(fpout);

    return 0;

}