readability - resulting grade is incorrect

Question

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

int main(void)

{
    string text = get_string("Text: ");
    float letters = 0;
    float words = 0;
    float sentences = 0;
    
    for (int i = 0, n = strlen(&text[i]); i < n; i++)
    {
        if (isalpha(text[i]))
        {
            letters++;
        }
        
    }
    printf("%.1f letter(s)\n", letters);
    
    for (int i = 0, n = strlen(&text[i]); i < n; i++)
    {
        if (isspace(text[i]))
        {
            words++;
        }
    }
    printf("%.1f word(s)\n", words + 1);
    
    for (int i = 0, n = strlen(&text[i]); i < n; i++)
    {
        if (text[i] == '!' || text[i] == '.' || text[i] == '?')
        {
            sentences++;
        }
    }
    printf("%.1f sentence(s)\n", sentences);
    
    float L = (100.00 * letters) / words;
    float S = (100.00 * sentences) / words;
    float index = 0.0588 * L - 0.296 * S - 15.8;
    int grade = round(index);
    
    printf("Average letters per 100 words: %.1f\n", L);
    printf("Average sentences per 100 words: %.1f\n", S);
    printf("Grade %i\n", grade);
    
}

This is what I'm getting when using the following text

Text: In my younger and more vulnerable years my father gave me some advice that I've been turning over in my mind ever since.
96.0 letter(s)
23.0 word(s)
1.0 sentence(s)
Average letters per 100 words: 436.4
Average sentences per 100 words: 4.5
Grade 9

But it's suppose to give me Grade 7, and something around 417 letters per 100 words 4.3 sentences per 100 words

So I assume the grade issue results in an error in calculating the averages, but I can't figure out what.

I've also tried

float L = (letters / words) * 100;
float S = (sentences/ words) * 100; 

but no luck either.

Answer 1

You're right, the calculations are wrong. Mostly because one value, words, is wrong.

Note that when the code prints out the value of words,it adds 1 to the value of words first. But it doesn't change the value of words, so later, it's wrong.

printf("%.3f word(s)\n", words + 1);

BUT, in the calculations, the value of words is off by 1.

Does that tell you what's going on? It's the issue of how to count the last word.

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