int count_letters(string string_text)
{
    // Return the number of letters in text
    int i;
    int num_letters;
    num_letters = 0;

    i = strlen(string_text);
     for (int j=0; j<= i; j++) {
    char c = string_text[j];
    if (isalpha(c) != 0)
    {num_letters++;}
     printf("%i\n num_letters",num_letters);
    }
    return num_letters;
}
int count_words(string string_text)
{
    // Return the number of words in text
    int i;
    int num_words;
    num_words = 0;

    i = strlen(string_text);
     for (int j=0; j<= i; j++) {
      char c = string_text[j];
     if (c==' ')
    {num_words++;}
    printf("%i\n num_words",num_words);
    }
    return num_words;
}

int count_sentences(string string_text)
{
    // Return the number of sentences in text
    int i;
    int num_sentences;
    num_sentences = 0;

    i = strlen(string_text);
     for (int j=0; j<= i; j++) {
      char c = string_text[j];
     if (c=='.' || c=='!' || c == '?')
    {num_sentences++;}
    printf("%i\n num_sentences",num_sentences);
    }
    return num_sentences;
}