Question

I have

no matching function for call to 'saveLine::saveLine()'

error when compiling my application. The construcor is never actually called.

saveLine class definition:

class saveLine
{
public:
    saveLine(QWidget *parent);
private:
    QPushButton *selectButton, *acceptButton;
    QLabel *filePath;
    QLineEdit *allias;
};

saveLine is used in another class which is defined as follows:

class MWindow : public QWidget
{
    Q_OBJECT
public:
    MWindow(QWidget *parent=0);
private:
    saveLine line1;
};

error points to MWindow constructor implementation

MWindow::MWindow(QWidget *parent):QWidget(parent)
{
    this->setWindowTitle("Launcher");
    this->resize(600,600);
}

What should i do? I intend to use saveLine class in a vector, to create lines at runtime.

EDIT: i’ve misdeclared line1, it should read

saveLine *line1;

but now it gives another error

ISO C++ forbids declaration of 'saveLine' with no type

and

expected ';' before '*' token

on this line. It seems like saveLine is no longer considered a class, how so?

Answer 1

but now it gives another error

ISO C++ forbids declaration of
‘saveLine’ with no type

You need to add a forward declaration to tell the compiler that saveLine class exists:

Like this:

//declare that there will be a class saveLine
class saveLine;

class MWindow : public QWidget
{
    Q_OBJECT
public:
    MWindow(QWidget *parent=0);
private:
    saveLine *line1;
};