diagonali

#include <iostream>
#define N 3

using namespace std;

int main() {
  int M[N][N];

  for (int i = 0; i < N; i++) {
    for (int j = 0; j < N; j++) {
      cin >> M[i][j];
    }
  }

  // Diagonale principale
  // i == j
  int diag_1 = 1;
  for (int i = 0; i < N; i++) {
    diag_1 = diag_1 * M[i][i];
  }

  // Diagonale secondaria
  // i = N - i - 1
  int diag_2 = 1;
  for (int i = 0; i < N; i++) {
    diag_2 = diag_2 * M[i][N - i - 1];
  }

  cout << "Diag 1: " << diag_1 << endl << "Diag 2: " << diag_2 << endl;

  return 0;
}