a question about feof()

#include<stdio.h>
#include<stdlib.h>
#define BUFSIZE 100
int main(int argc,char *argv[])
{
     if(argc!=3)
     {
          printf("please input in accordance with this format:"
                    " programeName sourceName DestName!\n");
          return 0;
     }

     FILE *pS,*pD;
     char *sfName,*dfName;
     char cbuffer[BUFSIZE]={0};
     
     sfName=argv[1];
     dfName=argv[2];

     if((pS=fopen(sfName,"rb"))==NULL)
     {
         printf("open soucefile %s unsuccessful!\n"
                  "maybe the soucefile is invalid!",sfName);
         exit(1);
     }
     if((pD=fopen(dfName,"wb"))==NULL)
     {
         printf("open destfile %s unsuccessful!\n",dfName);
         exit(1);
     }

     while(!feof(pS))
     {
              fread(cbuffer,sizeof(cbuffer),1,pS);
              if(ferror(pD))
              {
                   clearerr(pD);
                   printf("the write operation is unsuccessful\n");
                   exit(1);
              }
 
              fwrite(cbuffer,sizeof(cbuffer),1,pD);
              if(ferror(pD))
              {
                   clearerr(pD);
                   printf("the write operation is unsuccessful\n");
                   exit(1);
              }

     }
     fclose(pS);
     fclose(pD);
     return 0;
}