cap.c: new; rot.c: improved

1 files changed, 21 insertions, 18 deletions

diff --git a/rot.c b/rot.c
index ab3e80c..b5b8b00 100644
--- a/rot.c
+++ b/rot.c
@@ -13,24 +13,27 @@
 #include <ctype.h>
 #include <stdlib.h>
 
-#define mod(A) ((A)%26)
-
 int main(int argc, char **argv)
 {
-    if(argc!=3)
-        exit(1);
-    char *string = *(argv+1);
-    int i, rot = (int)strtol(*(argv+2), NULL, 10);
-    for(i=0; i<strlen(string); i++)
-        if(isalpha(string[i])){
-            if(string[i]-'A'<26){ // Simple way to differentiate lower and upper case if all letters are known to be alpha.
-                putchar(mod(string[i]-'A'+rot)+'A');
-            }else{
-                putchar(mod(string[i]-'a'+rot)+'a');
-            }
-        }else{
-            putchar(string[i]);
-        }
-    putchar('\n');
-    return 0;
+	if (argc != 3) {
+		printf("Incorrect number of arguments.\n");
+		exit(1);
+	}
+
+	int rot = strtol(argv[2], NULL, 10);
+	unsigned length = strlen(argv[1]);
+
+	for (unsigned i = 0; i < length; i++) {
+		if (isalpha(argv[1][i])) {
+			if (argv[1][i] - 'A' < 26)
+				putchar((argv[1][i] - 'A' + rot) % 26 + 'A');
+			else
+				putchar((argv[1][i] - 'a' + rot) % 26 + 'a');
+		} else
+			putchar(argv[1][i]);
+	}
+
+	putchar('\n');
+
+	return 0;
 }