// An isogram is a word, in which no letter of the alphabet 
// occurs more than once. Write a C program that reads in 
// words until Ctrl+D, and checks whether the word is an isogram. 

#include <stdio.h>
#include <string.h>
#include <ctype.h>

#define MAX 100

int is_isogram(char word[100]);

int main (void) {
    char word[MAX];

    while(fgets(word, MAX, stdin) != NULL) {
        word[strlen(word) - 1] = '\0';
        if(is_isogram(word)) {
            printf("This is an isogram\n");
        } else {
            printf("This is not an isogram\n");
        }
    }


    // PUT YOUR CODE HERE

    return 0;
}

int is_isogram (char word[100]) {
    int count[26] = {0};

    int i = 0;
    while (word[i] != '\0') {
        char c = tolower(word[i]);

        if (isalpha(c)) {
            if (count[c - 'a'] > 0) {
                // we have a letter that has been repeated
                return 0; 
            }
            count[c - 'a']++;
        }
        i++;
    }
    return 1;
}