Refactor strcmp function for improved readability and structure

Author: chrisdedman

user/string.c

@@ -10,26 +10,22 @@
  */
 int strcmp(const char *str_1, const char *str_2)
 {
-    unsigned char str1, str2;
-    while(1)
-    {
-      str1 = *str_1++;
-      str2 = *str_2++;
-      
-      if (str1 != str2)
-      {
-        // NOTE: If needed in the future, can return the difference between
-        // the strings rather than just -1 or 1
-        return str1 < str2 ? -1 : 1;
-      }
+  unsigned char ch1, ch2;
+  do
+  {
+    ch1 = *str_1++;
+    ch2 = *str_2++;
 
-      if (!str1)
-      {
-        break;
-      }
+    if (ch1 != ch2)
+    {
+      // NOTE: If needed in the future, can return the difference between
+      // the strings rather than just -1 or 1
+      return ch1 < ch2 ? -1 : 1;
     }
 
-    return 0;
+  } while (ch1);
+
+  return 0;
 }
 
 /**