blob: 283363f5844c44c0f4177b9a11b8b0fa22023c81 (
plain) (
tree)
|
|
#include "isogram.h"
#include <ctype.h>
#include <string.h>
bool is_isogram(const char phrase[]) {
if (phrase == NULL) return false;
bool seen[26] = {0};
for (size_t idx = 0; phrase[idx] != '\0'; idx++) {
unsigned char cur = tolower((unsigned char) phrase[idx]);
if ('a' <= cur & cur <= 'z') {
size_t s_idx = cur - 'a';
if (seen[s_idx]) return false;
else seen[s_idx] = true;
}
}
return true;
}
|