printMatrix

#include <iostream>
#include <iomanip>

void printMatrix(int l, int n, double *A, int r) {
    int rows_to_show = std::min(l, r);
    int cols_to_show = std::min(n, r);
    for (int i = 0; i < rows_to_show; ++i) {
        for (int j = 0; j < cols_to_show; ++j) {
            std::cout << " " << std::scientific << std::setprecision(3) << A[i * n + j];
        }
        std::cout << std::endl;
    }
}