/*
    char.c

    Written by Tanya Amert for Fall 2024.

    Demonstrates working with char arrays in C, as well as
    how values stored in a char can be printed different ways.

    To compile this program:

        gcc -Wall -Werror -g -o char char.c

    To run this program:

        ./char
*/

#include <stdio.h>

// We can use "#define"s to do things like set a flag for debugging.
// We'll talk more about what these are later.  When DEBUG is set to 1
// the program prints out extra messages for debugging; if it's anything
// else (say, 0), then the debugging prints won't appear.
#define DEBUG 1

// By very common convention, main() will appear at the top of many of
// my C samples.  But if main appears before a function that it calls,
// the compiler won't recognize the function in main, so you'll get an
// error.  It is thus common to provide "function prototypes" (i.e.,
// declaration of function signatures without the corresponding function
// bodies) at the top, before main.  Function prototypes also appear in
// *.h files for similar reasons.
int get_aA_count(char arr[], int n);

// Calls another function to count the number of a/A characters
// in a char array.
int main()
{
    // Create a 6-element char array for us to work with
    char some_bytes[6] = { 10, 42, 65, 88, 97, 125 }; // fun: change one to 8

    // Call another function to do the work
    int num_aA = get_aA_count(some_bytes, 6);

    // Print the results
    printf("Found %d characters that were either 'a' or 'A'.\n", num_aA);

    // By convention, we should return 0 to indicate successful completion
    // of this program.
    return 0;
}

// Returns the number of 'a' and 'A' characters in a given array.
// Prints some helpful debugging info along the way.
//
// Inputs:
//   arr: a char array
//   n: the number of chars in arr
//
// Returns: the number of chars equal to 'a' or 'Z'
int get_aA_count(char arr[], int n)
{
    int count = 0;

    // We can use a for loop to iterate through the array
    for (int i = 0; i < n; i++)
    {
        char current_char = arr[i];

        // If we're printing debugging messages, print the current char
        if (DEBUG == 1)
        {
            // We can use %c for the ASCII character representation (e.g., 'A')
            // and %d for the decimal number (e.g., 65)
            printf("Current char: '%c' (decimal: %d)\n", current_char, current_char);
        }

        // If this character is an 'a' or 'A' (e.g., decimal 97 or 65),
        // increment our counter by 1
        if ((current_char == 'a') || (current_char == 'A'))
        {
            count++;
        }
    }

    return count;
}