#include <cs50.h>
#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <math.h>

int count_letters(string text);
int count_words(string text);
int count_sentences(string text);
int main(void)

{
    // Enter the text of reading
    string text = get_string("Text: ");
    int letters = count_letters(text);
    int words = count_words(text);
    int sentences = count_sentences(text);

    // Coleman-Liau Index
    int L = (float)letters / (float)words * 100;
    int S = (float)sentences / (float)words * 100;
    int grade = round(0.0588 * L - 0.296 * S - 15.8);
    if (grade >= 16)
    {
        printf("Grade 16+\n");
    }
    else if (grade < 1)
    {
        printf("Before Grade 1\n");
    }
    else
    {
        printf("Grade %i\n", grade);
    }
}

// Find number of letters/words/sentences in text
int count_letters(string text)
{
    int i = 0;
    int letters = 0;
    for (i = 0; i < strlen(text); i++)

    if (isalnum(text[i]))
    {
        letters++;
    }
    return letters;
}

int count_words(string text)
{
    int words = 1;
    int i = 0;
    for(i = 0; i < strlen(text); i++)
    if (isalnum(text[i]) && isblank(text[i - 1]))
    {
        words++;
    }
    return words;
}

int count_sentences(string text)
{
    int sentences = 0;
    int i = 0;
    for(i = 0; i < strlen(text); i++)
    if (i > 0 && (text[i] == '.' || text[i] == '!' || text[i] == '?') && isalnum(text[i - 1]))
    {
        sentences++;
    }
    return sentences;
}