#include <stdio.h>

int main(int argc, char *argv[])
{
    if(argc != 2) {
        printf("ERROR: You need one argument.\n");
        return 1;
    }

    int i = 0;
    char letter;
    int up_low_sep = (int)('a' - 'A');
    int upper_floor = (int)'A';
    int upper_ceil = (int)'Z';

    for(i = 0; '\0' != (letter = argv[1][i]); i++) {
        char letter = argv[1][i];
        int i_letter = (int)letter;
        if (upper_floor < i_letter && i_letter < upper_ceil) {
            letter = (char)(i_letter + up_low_sep);
        }

        switch(letter) {
            case 'a':
                printf("%d: 'a'\n", i);
                break;

            case 'e':
                printf("%d: 'e'\n", i);
                break;

            case 'i':
                printf("%d: 'i'\n", i);
                break;

            case 'o':
                printf("%d: 'o'\n", i);
                break;

            case 'u':
                printf("%d: 'u'\n", i);
                break;

            case 'y':
                if (i > 2) {
                    printf("%d: 'Y'\n", i);
                } else {
                    printf("%d: 'Y' isn't a vowel this time\n", i);
                }
                break;

            default:
                printf("%d: '%c' is not a vowel\n", i, letter);
        }
    }

    return 0;
}