阅读以下程序,对程序功能的描述中正确的是 #icnlude int main() { FILE *in, *out; char ch, infile[10], outfile[10]; printf("Enter the infile name:"); scanf("%s", infile); printf("Enter the outfile name:"); scanf("%s", outfile); if ((in = fopen(infile, "r")) == NULL) { printf("cannot open infile."); exit(0); } if ((out = fopen(outfile, "w")) == NULL) { printf("cannot open outfile."); exit(0); } while (!feof(in)) { fputc(fgetc(in), out); } fclose(in); fclose(out); return 0; }