阅读以下程序及对程序功能的描述,其中正确的描述是 #include main() { FILE *in,*out char ch,infile[10],outfile[10] printf('Enter the infile name:\n') scanf('%s',infile) printf('Enter the outfile name:\n') scanf('%s',outfile) if((in=fopen(infile,'r'))==NULL) { printf('cannot open infile\n') exit(0) } if((out=fopen(outfile,'w'))==NULL) { printf('cannot open outfile\n') exit(0) } while(! feof(in))fputc(fgetc(in),out) fclose(in) fclose(out) }