Big update: 5/N fix

coreutils/cmp.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <errno.h>
 #include <string.h>
+#include <unistd.h>
 #include <stdlib.h>
 unsigned int s_flag;
 
@@ -53,45 +54,48 @@ FILE *file_open(const char *path) {
 	return fp;
 }
 
-int main(const int argc, const char **argv) {
-	int i;
-	for (i = 1; i < argc; i++) {
-		if (argv[i][0] != '-')
-			break;
+int main(int argc, char **argv) {
+	int opt;
+	while ((opt = getopt(argc, argv, "f")) != -1) {
+		switch (opt) {
+			case 'f':
+				s_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-n"))
-			s_flag = 1;
-
-		else if (!strcmp(argv[i], "--help")) {
-			printf("cmp FILE1 FILE2 [SKIP1] [SKIP2]\n\t[-f Silent]\n");
-			return 0;
+			default:
+				printf("cmp file1 file2 [skip1] [skip2]\n\t[-f Silent]\n");
+				return 0;
 		}
 	}
 
 
+	argv += optind;
+	argc -= optind;
+
 	long skip1 = 0;
 	long skip2 = 0;
 	FILE *fp1 = NULL;
 	FILE *fp2 = stdin;
 
-	switch (argc - i) {
+	switch (argc) {
 		case 4:
-			skip2 = parse_int(argv[i + 3]);
+			skip2 = parse_int(argv[3]);
 			/* fallthrough */
 
 		case 3:
-			skip1 = parse_int(argv[i + 2]);
+			skip1 = parse_int(argv[2]);
 			/* fallthrough */
 
 		case 2:
-			fp2 = file_open(argv[i + 1]);
+			fp2 = file_open(argv[1]);
 			/* fallthrough */
 
 		case 1:
-			fp1 = file_open(argv[i]);
+			fp1 = file_open(argv[0]);
 			break;
 
 		default:
+			fprintf(stderr, "cmp: missing operand\n");
 			return 1;
 	}