#include <stdlib.h>
#include <stdio.h>
void  main()
  {FILE *fp;
   char ch,filename[10];
   scanf("%s",filename);
   if((fp=fopen(filename,"w"))==NULL)
      {
       printf("cannot open file\n");
       exit(0);
       }
   ch=getchar( );
   ch=getchar( );
   while(ch!='#')
    {
      fputc(ch,fp);
      putchar(ch);
      ch=getchar();
     }
   fclose(fp);
   putchar(10);
  }
请问为什么要有两个ch=getchar();