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

void mul(int **a, int **b, int **c, int n) {
    int i, j, k, sum;
    for (i = 0; i < n; i++) {
        for (j = 0; j < n; j++) {
            sum = 0;
            for (k = 0; k < n; k++) {
                sum += a[i][k] * b[k][j];
            }
            c[i][j] = sum;
        }
    }
}

int main() {
    int i, j, n = 2;
    
    int ary_a[2][2]={{1,2},{3,4}};
    int ary_b[2][2]={{5,6},{7,8}};
    
    // 動態分配記憶體給矩陣
    int **arr_a = (int **)malloc(n * sizeof(int *));
    int **arr_b = (int **)malloc(n * sizeof(int *));
    int **arr_c = (int **)malloc(n * sizeof(int *));
    
	if (arr_a == NULL || arr_b == NULL || arr_c == NULL) {
        printf("記憶體分配失敗\n");
        return 1;
    }
    
    for (i = 0; i < n; i++) {
        arr_a[i] = (int *)malloc(n * sizeof(int));
        arr_b[i] = (int *)malloc(n * sizeof(int));
        arr_c[i] = (int *)malloc(n * sizeof(int));
        
        if (arr_a[i] == NULL || arr_b[i] == NULL || arr_c[i] == NULL) {
        printf("記憶體分配失敗\n");
        return 1;
    	}
    }
    
	for (i = 0; i < 2; i++) {
	        for (j = 0; j < 2; j++) {
	            arr_a[i][j] = ary_a[i][j];
	            arr_b[i][j] = ary_b[i][j];
	        }
	    }
    
    // 進行矩陣乘法
    mul(arr_a, arr_b, arr_c, n);
    
    // 輸出結果
    for (i = 0; i < n; i++) {
        for (j = 0; j < n; j++) {
            printf("arr_c[%d][%d] = %d\n", i, j, arr_c[i][j]);
        }
    }
    
    // 釋放記憶體
    for (i = 0; i < n; i++) {
        free(arr_a[i]);
        free(arr_b[i]);
        free(arr_c[i]);
    }
    free(arr_a);
    free(arr_b);
    free(arr_c);
    
    return 0;
}