#include#include using Eigen::MatrixXd; int main() { MatrixXd m(3,3); m << 1,2,3, 4,5,6, 7,8,9; std::cout << "Number of columns: " << m.cols() << std::endl; return 0; }
Number of columns: 3
#include#include using Eigen::MatrixXd; int main() { MatrixXd m(2,4); std::cout << "Number of columns: " << m.cols() << std::endl; return 0; }
Number of columns: 4In this example, we create a 2x4 matrix `m` and print the number of columns. This shows that `cols()` works even if the matrix has a different size than the previous example. Eigen is a package library that provides a robust implementation of linear algebraic operations.