Determinant by Rule of Sarrus

// Determinant by Rule of Sarrus

#include <iostream>
#include <ctime>

using std::cout;
using std::cin;
using std::endl;

void main()
{

    srand(time(0));

    double matrix[3][3];

    for (int i = 0; i < 3; ++i)
    for (int j = 0; j < 3; ++j)
        matrix[i][j] = rand() % 20 - 10;


    double det = matrix[0][0] * matrix[1][1] * matrix[2][2] + matrix[1][0] * matrix[0][2] * matrix[2][1] +
        matrix[0][1] * matrix[1][2] * matrix[2][0] - matrix[2][0] * matrix[1][1] * matrix[0][2] -
        matrix[0][1] * matrix[1][0] * matrix[2][2] - matrix[0][0] * matrix[1][2] * matrix[2][1];


    double det2 = 0.0;

    for (int i = 0; i < 3; i++)
    {
        for (int j = 0; j < 3; j++)
        {
            if (j == i) continue;
            int k = 3 - i - j;
            double x = matrix[0][i] * matrix[1][j] * matrix[2][k];
            x *= ((i - j) * (j - k) *( k - i) > 0) ? 1 : -1;
            det2 += x;
        }
    }

    cout << det << endl;
    cout << det2 << endl;

}