阅读以下程序以及对程序功能的描述,其中正确的描述是( )。 #include <stdio.h> main() { FILE * in,*out; charch,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); }