Question

I’m doing a program that is asking the user to enter a stream of characters and printing out the number of uppercase and lowercase letters. I’m trying to do it with a function, but having some trouble printing it..for every character input im entering im getting 0, 0
Would appreciate your help to understand what am I doing wrong:

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

int case_letters(int ch);

int main(void)

{
    int x;
    printf("please enter a some characters, and ctrl + d to see result\n");

    case_letters(x);

    return 0;
}

int case_letters(int ch)

{
    int numOfUpper = 0;
    int numOfLower = 0;

    while ((ch = getchar()) != EOF)
    {
        if ((ch = isdigit(ch)) || ch == '\n')
        {
            printf("please enter a valid character\n");
            continue;
        }


        else if ((ch = isupper(ch)))
        {
            numOfUpper++;
        }

        else if ((ch = islower(ch)))
        {
            numOfLower++;
        }

    }

    return  printf("%d, %d", numOfUpper, numOfLower);
}

Answer 1

All of your if statements assign different value to ch and do not check ch‘s value.

For example, if you enter a correct char, this

if ((ch = isdigit(ch)) || ch == '\n')

will assign 0 to ch, because isdigit(ch) will return 0. I guess you need

if ( isdigit(ch) || ch == '\n')

Same for islower and isupper.