#include <stdio.h>
#include <stdlib.h>

//as simple as possible: given n, and 2d array, go through it using 2 nested 'for' loops
void printMagicSquare(int n, int magicSquare[n][n], int magicConstant) {
    printf("Magic Square of Order %d:\n", n);
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            printf("% 3d ", magicSquare[i][j]);
        }
        printf("\n");
    }
    printf("\nMagic Constant: %d\n\n", magicConstant);
}

void generateMagicSquare(int n) {
    if (n % 4 != 0) {
        printf("Please enter a valid doubly even order (4, 8, 12, etc.)\n");
        exit(1);
    }

    int magicSquare[n][n];
    int count = 1;
    int magicConstant = (n * n + 1) * n / 2;

    //alternatively use memset
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            magicSquare[i][j] = 0;
        }
    }

    //this is heavy duty part
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if ((i % 4 == 0 && j % 4 == 0) || (i % 4 == 3 && j % 4 == 3)) {
                magicSquare[i][j] = count;
            } else if ((i % 4 == 1 && j % 4 == 1) || (i % 4 == 2 && j % 4 == 2)) {
                magicSquare[i][j] = count;
            } else {
                magicSquare[i][j] = n * n - count + 1;
            }
            count++;
        }
    }

    printMagicSquare(n, magicSquare, magicConstant);
}

int main() {
    int n;

    printf("Enter doubly even number (n >= 4, e.g. 4, 8, 12) for the order of the magic square: ");
    scanf("%d", &n);

    generateMagicSquare(n);

    return 0;
}