#include <iostream>

using namespace std;

void swap(int a[][3], int b[][3], int r, int c);

int main()
{
    int a[3][3] = {
        {0, 1, 2},
        {3, 4, 5},
        {6, 7, 8}
    };

    int b[3][3] = {
        {20, 21, 22},
        {23, 24, 25},
        {26, 27, 28}
    };

    for (int r = 0; r < 3; r++)
    {
        for (int c = 0; c < 3; c++)
        {
            if (r == c)
            {
                swap(a, b, r, c);
            }
        }
    }

    cout << a[0][0];
}

void swap(int &a, int &b, int r, int c)
{
    int temp = a;
    b[r][c] = a;
    a[r][c] = temp;
}