Why does my letter counter display 0 when put in a function-CodePudding

I'm very new to C and trying to create a counter for how many times the letter "a" appears in a string. I get it working by putting it directly into main, however when I put it into a function, my printf outputs 0.

#include <stdio.h>
#include <string.h>
#define STRING_LENGTH 50

void letter_counter(char input[STRING_LENGTH], int count, char letter ) {
    int i;
    for (i = 0; i < strlen(input); i  ){
    if (input[i] == letter) {
        count  ;
}
}
}


int main() {

    int a1 = 0;
    char a = 'a';

    printf("Please write a word\n");

    char input[STRING_LENGTH] = {0};
    fgets(input,STRING_LENGTH,stdin);
    input[strlen(input) - 1] = 0;

    letter_counter(input, a1, a);
    printf("%i\n", a1);




}

CodePudding user response：

You are not returning the value of what you have counted. It looks like you think that a1 is going to contain the total, but it's not.

Your letter_counter function needs to return an int value, not void.

int letter_counter(char input[STRING_LENGTH], char letter ) {
    int i;
    int count = 0;

    for (i = 0; i < strlen(input); i  ){
    if (input[i] == letter) {
        count  ;
    }

    return count;
}

Then you need to assign the return value of the function to a variable:

a1 = letter_counter(input, a);