Contents

#include "isogram.h"
#include <ctype.h>
#include <stddef.h>
#include <stdint.h>

bool is_isogram(const char phrase[])
{
   uint32_t used_letters = 0;

   if (phrase == NULL)
      return false;

   for (int16_t i = 0; phrase[i] != '\0'; ++i) {
      if (isalpha(phrase[i])) {
         uint8_t bit_number = toupper(phrase[i]) - 'A';
         uint32_t bit_mask = 1 << bit_number;

         if ((used_letters & bit_mask) > 0)
            return false;
         else
            used_letters |= bit_mask;
      }
   }

   return true;
}

Version data entries

136 entries across 136 versions & 1 rubygems

Version	Path
trackler-2.2.1.139	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.138	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.137	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.136	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.135	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.134	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.133	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.132	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.131	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.130	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.129	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.128	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.127	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.126	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.125	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.124	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.123	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.122	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.121	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.120	tracks/c/exercises/isogram/src/example.c