Exer4.6.c(undone)

//程式可以正常運行，但file.nohole始終沒有東西寫進去，為什嗎？

 #include "apue.h"#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>  int main(int argc, char *argv[]){  FILE *fp1, *fp2;   char chr;  int fd, count = 0;   if(argc != 3)    err_quit("Usage: %s <src> <dest>", argv[0]);   if((fp1 = fopen(argv[1], "r")) == NULL)    err_sys("fopen %s error", argv[1]);  if((fd = open(argv[2], O_CREAT|O_EXCL|O_TRUNC, S_IRWXU|S_IRGRP)) < 0)    err_sys("create %s error", argv[2]);  if((fp2 = fdopen(fd, "rw")) == NULL)    err_sys("transfer from filedes to file stream error");  while((chr = getc(fp1)) != EOF){    count++;    if(!chr){      continue;    }     putc(chr, stdout);    printf("\ncount: %d\n", count);       putc(chr, fp2);  }  //  putc(EOF, stdout); // '?' printed  putc(EOF, fp2);  fflush(fp2);  if(fclose(fp2) == EOF)    err_sys("fclose fp2 error");  exit(0);}