// This program will print out an array of arrays
// Welcome to 2D arrays!

// Declare and create a 3 x 3 two-dimensional array of integer numbers 
// with the numbers read in from the user. Then loop through the 
// two-dimensional array, printing out the values in the first row followed 
// by those in the second row and so on.

// Let's extend it to loop through the array to count the number 
// of even numbers in the 2D array

// Week 4: Lecture 7 - 2D Arrays

#include <stdio.h>

#define MAX_ROW 3
#define MAX_COL 3

void print_array(int array[MAX_ROW][MAX_COL]);
int count_even(int array[MAX_ROW][MAX_COL]);

int main(void) {

    // Declare an array of arrays that will be able to house user input 
    int array[MAX_ROW][MAX_COL];
    // You can also declare and initialise in this way:
    // int array2[][] = {{1, 2, 3}, {1, 2, 3}, {4, 5, 6}};
    // Variable names i and j are perfectly okay here instead of row and col
    // Will first demonstrate with row and col so you see the way it moves
    int row = 0;
    int col = 0;

    for(row = 0; row < MAX_ROW; row++) {
        for (col = 0; col < MAX_COL; col++) {
            printf("Enter a number: ");
            scanf("%d", &array[row][col]);
        }
    }
    
    // Call the function to print out the 2D array here:
    print_array(array);
    
    // Call the function to count even numbers:
    printf("The number of even numbers in the 2D array is %d\n", count_even(array));


    return 0;
}

// Function to print out a 2D Array
// INPUT: array 
// OUTPUT: void
// Name: print_array

void print_array(int array[MAX_ROW][MAX_COL]) {
    for(int row = 0; row < MAX_ROW; row++) {
        for(int col = 0; col < MAX_COL; col++){
            printf("%d", array[row][col]);
        }
        printf("\n");
    }
}

// Function to count the number of even numbers in 2D array
// INPUT: array (2D)
// OUTPUT: int (count of the evens)
// name: count_even
int count_even(int array[MAX_ROW][MAX_COL]) {
    int count = 0;
    for(int row = 0; row < MAX_ROW; row++) {
        for(int col = 0; col < MAX_COL; col++) {
            if(array[row][col] % 2 == 0) {
                count++;
            }
        }
    }
    return count;
}