exercism

commit 004533a2cbcb2a5cd216a83334dc8b583a0c9aab
parent 2560772f48154bf035fbf381d6a9b7554dd2799c
Author: dwrz <dwrz@dwrz.net>
Date:   Sun, 24 Feb 2019 14:59:00 +0000

Reformat and document c/isogram

Diffstat:
M
c/isogram/src/isogram.c
 | 
19
++++++++-----------

1 file changed, 8 insertions(+), 11 deletions(-)
diff --git a/c/isogram/src/isogram.c b/c/isogram/src/isogram.c
@@ -3,14 +3,12 @@
 
 int length(const char string[]) {
   int i = 0;
-  while (string[i] != '\0') {
-    i++;
-  }
-  return i+1; // Account for terminating null character.
+  while (string[i] != '\0') { i++; }
+  return i+1; // Account for terminating null char.
 }
 
 char lowercase(char c) {
-  // Lowercase only ASCII capital characters.
+  // Lowercase only ASCII uppercase chars.
   if (c >= 65 && c <= 90) {
     return c + 32;
   }
@@ -18,11 +16,11 @@ char lowercase(char c) {
 }
 
 bool is_symbol_char(char c) {
-  // Ignore symbols that precede alpha chars.
+  // Catch chars that precede or follow alpha chars.
   if (c < 65 || c > 122) {
     return true;
   }
-  // Ignore symbols intervening the upper and lowercase chars.
+  // Catch chars intervening the upper and lowercase alpha chars.
   if (c > 90 && c < 97) {
     return true;
   }
@@ -32,14 +30,13 @@ bool is_symbol_char(char c) {
 bool is_isogram(const char phrase[]) {
   if (phrase == NULL) { return false; }
   if (length(phrase) == 0) { return true; }
-  // There are 26 lowercased ASCII alpha chars.
+  // There are 26 lowercased ASCII alpha chars (97-122).
   // We can use 26 indexes to keep track of each one.
   char char_map[26] = { 0 };
   for (int i = 0; i < length(phrase); i++) {
     if (is_symbol_char(phrase[i])) { continue; } // Ignore non-alpha chars.
-    if (char_map[lowercase(phrase[i]) - 97] != 0) {
-      return false;
-    }
+    if (char_map[lowercase(phrase[i]) - 97] != 0) { return false; }
+    // Keep track of chars by incrementing the index value.
     char_map[lowercase(phrase[i]) - 97]++;
   }
   return true;