Count all characters in a string but spaces

Question

I have so far, in my C code where it counts everything in a user given string, however, I only want it to count letters.

Whenever I try and take out or change the spaces counter my code ends up breaking and forces me to manually stop it.

I would like to use the spaces sometime later as a method to count words but I'd rather try and get the letters done first.

What I mean by it breaks is that the code will proceed to infinitely do nothing. I found this out when instead of putting something down I had it printed and it constantly repeated what was given with no stopping.

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

int main(void)
{   
    string s = get_string("Text: ");
    int n = 0;

    while (s[n] != '\0')
    {
        if (isalpha(s[n])) //counts letters
        {
            n++;
        }
        else
        {

        }
    }

I would like to try and keep the code similar, but if its easier, a different way.

Also I would like to keep it to where it will be able to process a string given by the user.

Answer 1

If you look closely at the cycle:

while (s[n] != '\0')
{
    if (isalpha(s[n])) //counts letters
    {
        n++;
    }
}

you will notice that when s[n] is not alpha, n is not incremented, so you're stuck in an infinite loop.

The counter and the iterator should be different variables:

int count = 0;
//...
while (s[n] != '\0')
{
    if (isalpha(s[n])) 
    {
        count++; //counts letters
    }
    n++; //increment iterator
}

Answer 2

You have an infinite loop as soon as a non letter character is encountered due to the else statement

int n = 0;

while (s[n] != '\0')
{
    if (isalpha(s[n])) //counts letters
    {
        n++;
    }
    else
    {

    }
}

You have to use two variables. The first one is to store the number of letters and the second one is to traverse a character array.

In such a case it is better to use the for loop instead of the while loop.

For example

size_t n = 0;

for  ( size_t i = 0; s[i] != '\0'; i++ )
{
    if ( isalpha( ( unsigned char )s[i] ) ) //counts letters
    {
        n++;
    }
}

Pay attention to that there is no sense to declare the variable n as having the signed integer type int . It is better to declare it as having the unsigned integer type size_t . It is the type that for example the string function strlen has.