Run function when push button is clicked - c++

Question

I am using the Qt add in for visual studio. Now I made a simple push button using Qt designer, and I want to use that push button so that it runs a function with a certain inputparameter when it is pressed, and then displays the result that is printed by the function.
The function that I want to run uses the eigen library so requires #include <Eigen/Dense> and should be called as follows:
void coef(Eigen::Matrix<long double, Dynamic, Dynamic> vector, Eigen::Matrix<long double, Dynamic, Dynamic> Matrix)
After I made the push button in Qt designer it automatically already added some code to my header file.
Now I adjusted this header file to the following:
#ifndef QTDEMO_H
#define QTDEMO_H
#include <QtWidgets/QMainWindow>
#include "ui_qtdemo.h"
class qtdemo : public QMainWindow
{
Q_OBJECT
public:
qtdemo(QWidget *parent = 0);
~qtdemo();
private:
Ui::qtdemoClass ui;
// begin new code
public slots:
void on_btnHello_clicked() {
ui.btnHello->coef(v, A); // v and A are defined in main.cpp, so not in this header file
}
// end new code
};
#endif // QTDEMO_H
I know this would of course not work because
the Eigen libary is unknown to this header,
v and A are unknown to this header
3) the function coef() is unknown to this header file.
However, I am unexperienced with using header files, so I don't know what to do to make it work. Could anyone please help? Thanks in advance.

Answer 1

You would need to do the following:
1) #include <Eigen/Dense> in this file.
2) ui.btnHello->coef(v, A); -> coef(v, A);
3) Move v and A as const member variables into this class or make them static here. Although, it would be better to move the implementation into your qtdemo.cpp source file and only leave the declaration in the header.