Learn C the Hard Way Example 13

ex13.c

#include <stdio.h>

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

    int i;
    char letter;
    for(i = 0, letter = argv[1][i]; '\0' != argv[1][i]; i++, letter = argv[1][i])
    {
        switch(letter)
        {
            case 'a':
            case 'A':
                printf("%d: 'A'\n", i);
                break;

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

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

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

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

            case 'y':
            case 'Y':
                if(i > 2)
                    printf("%d: 'Y'\n", i);
                break;
            
            default:
                printf("%d: %c is not a vowel\n", i, letter);
                break;
        }
    }
    return 0;
}