#include <iostream>

using namespace std;

int main(int argc, char** argv) {
  constexpr int kRows = 2;
  constexpr int kCols = 3;
  int arr[kRows][kCols] = {{1,2,3},{4,5,6}};
  for (int r = 0; r < kRows; ++r) {
    for (int c = 0; c < kCols; ++c)
      cout << arr[r][c] << " ";
    cout << endl;
  }

  for (int r = 0; r < kRows; ++r)
    for (int c = 0; c < kCols; ++c)
      cout << &(arr[r][c]) - &(arr[0][0]) << " ";
  return 0;
}

// Output:
// 1 2 3
// 4 5 6
// 0 1 2 3 4 5