CODEWITHSUNDEEP
c++qtfunctionpublic
Jon CO
Jon CO

Reputation: 25

QT calling functions in different sources

In my project I've created multiple gui pages. In a secondary source (secondary.cpp) I want to call a function that declared in my mainwindow.cpp. I'm not really sure how to do this.

I've tried to declare the function at public section like:

QString format (QString number);

And definition in the mainwindow.cpp like: 

QString MainWindow::format(QString number) 
{
   ...
}

Then i include #include "mainwindow.h" in my secondary source (secondary.cpp) and calling the function with lower = format(upper); but I'm getting an error message:

format was not declared in this scope.

I've also tried calling it by

lower = MainWindow::format(upper);

which gives me the error message

Cannot call member function QString MainWindown::format(Qstring) without object.

Finaly I also tried to make a class in my mainwindow.h 

class test : public QString
{
public:
     QString format (QString number);
};

With QString test::format(QString number) in my mainwindow.cpp calling the function by lower = test::format(upper); this gives me the error:

Cannot call member function QString MainWindown::format(QString) without object.

I'm not convinced that I need to create a new class, but I thought I'd try anyway.

Upvotes: 0

Views: 2165

Answers (2)

t3ft3l--i
t3ft3l--i

Reputation: 1412

You need to create object of MainWindow class, then call function:

MainWindow *w = new MainWindow;
QString lower = w->format(upper);

Or another solution is static function of class. This way you have no needed create object of class and can call method by name like this:

QString lower = MainWindow::format(upper);

Of course you need to include your #include "mainwindow.h" header.

But you should know that MainWindow class is not the best place storing function for formation string, you can use QString class function like QString::toUpper() or QString::toLower() or create your own class for formating:

class myFormatingStringClass {
     QString toLower(QString str);
     static QStrin toUpper(QString str);
}

As i said above this way you will need to create object of myFormatingStringClass for using myFormatingStringClass::toLower() function or using static method:

QString upper = QString("Hello World");
myFormatingStringClass formating;
QString lower = formatin.toLower(upper);                // Using class method of existing object
QString upper = myFormatingStringClass::toUpper(lower); // Using static method

Upvotes: 2

Telokis
Telokis

Reputation: 3389

You can't do test::format(...) to call a non-static member function.

It must be bound to an object (an instance of your class). For example, you can do this :

test testObject;
QString formattedString = testObject.format(strToFormat);

Upvotes: 1

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