1 Array44i a = Array44i::Random(); 2 cout << "Here is the array a:" << endl << a << endl; 3 cout << "Here is a.leftCols(2):" << endl; 4 cout << a.leftCols(2) << endl; 5 a.leftCols(2).setZero(); 6 cout << "Now the array a is:" << endl << a << endl; 7