Make a 4x4 matrix

#include <iostream>
using namespace std;

int main() {
  int n = 4;
  int m;
  for (int i = 0; i < n; i++) {
    m = 0;
    while (m < n) {
      cout << 1 << " ";
      m++;
    }
    cout << endl;
  }
  return 0;
}