1 Matrix3i m = Matrix3i::Random(); 2 cout << "Here is the initial matrix m:" << endl << m << endl; 3 int i = -1; 4 for(auto c: m.colwise()) { 5 c *= i; 6 ++i; 7 } 8 cout << "Here is the matrix m after the for-range-loop:" << endl << m << endl; 9 auto cols = m.colwise(); 10 auto it = std::find_if(cols.cbegin(), cols.cend(), __anon685287db0102(Matrix3i::ConstColXpr x) 11 [](Matrix3i::ConstColXpr x) { return x.squaredNorm() == 0; }); 12 cout << "The first empty column is: " << distance(cols.cbegin(),it) << endl; 13