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-2.2.1.119	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.118	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.117	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.116	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.115	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.114	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.113	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.111	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.110	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.109	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.108	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.107	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.106	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.105	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.104	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.103	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.102	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.101	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.100	tracks/c/exercises/isogram/src/example.c
trackler-2.2.1.99	tracks/c/exercises/isogram/src/example.c