Facing problem in creating new cpp and Header file

[anda_skoa]

class Labeltext : public QPlainTextEdit

Are you sure your Labeltext class should be a QPlainTextEdit?

Labeltext(QLabel *parent = 0);

And you are sure you have a QLabel as its parent, not some container widget?

Cheers,
_

[parulkalra14]

Label is contain in Frame in my GUI so parent of labeltext should QFrame only..
So Labeltext(QLabel *parent = 0); is replaced with Labeltext(QFrame *parent = 0);

and Class Labeltext should inherit properties from Class Label.
So class Labeltext : public QPlainTextEdit is with class Labeltext : public QLabel

Am i correct now?

[anda_skoa]

Yes, that sounds a lot better

Cheers,
_

[parulkalra14]

So labeltext.cpp contain only one function void labtext(). So how to call this function from mainwindow.cpp?

#include "labeltext.h"
#include<QFrame>
#include<QLabel>
 
Labeltext::Labeltext(QFrame *parent) :QLabel(parent)
{
 
}
 
void labtext()
{
    if(cursor.block().text().contains("",Qt::CaseInsensitive))
   {
           ui->label->setText("");
 
   }
 
    if(cursor.block().text().contains("printf",Qt::CaseInsensitive)&& cursor.block().text().contains("(",Qt::CaseInsensitive)||cursor.block().text().contains("cout",Qt::CaseInsensitive)&&cursor.block().text().contains("<<",Qt::CaseInsensitive))
   {
           ui->label->setText("Printing to Standard Output");
   }
 
    else if(cursor.block().text().contains("while",Qt::CaseInsensitive)&& cursor.block().text().contains("(",Qt::CaseInsensitive))
   {
       ui->label->setText("Checking condition for While Statement");
 
   }
}

#include "labeltext.h"
#include<QFrame>
#include<QLabel>

Labeltext::Labeltext(QFrame *parent) :QLabel(parent)
{

}

void labtext()
{
    if(cursor.block().text().contains("",Qt::CaseInsensitive))
   {
           ui->label->setText("");

   }

    if(cursor.block().text().contains("printf",Qt::CaseInsensitive)&& cursor.block().text().contains("(",Qt::CaseInsensitive)||cursor.block().text().contains("cout",Qt::CaseInsensitive)&&cursor.block().text().contains("<<",Qt::CaseInsensitive))
   {
           ui->label->setText("Printing to Standard Output");
   }

    else if(cursor.block().text().contains("while",Qt::CaseInsensitive)&& cursor.block().text().contains("(",Qt::CaseInsensitive))
   {
       ui->label->setText("Checking condition for While Statement");

   }
}

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[anda_skoa]

So labeltext.cpp contain only one function void labtext(). So how to call this function from mainwindow.cpp?

I am not sure I understand the question, a method call is basic C++

pointerToLabelTextObject->labtext();

pointerToLabelTextObject->labtext();

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Cheers,
_

[parulkalra14]

Its not working showing Error undefined reference to Labeltext::labtext();
I declared class object in mainwindow.h like
Labeltext *labeltext;

and i called labtext() with the help of class Labeltext object i.e labeltext in this way :

labeltext->labtext()

[anda_skoa]

That is a linker error, so make sure that the code for labtext() is actually compiled. I.e. make sure that the respective source file is listed in SOURCES in your .pro file.

Cheers,
_

[d_stranz]

If this is what your .cpp file really looks like:

Labeltext::Labeltext(QFrame *parent) :QLabel(parent)
{
 
}
 
void labtext()
{
...
}

Labeltext::Labeltext(QFrame *parent) :QLabel(parent)
{

}

void labtext()
{
...
}

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then you have not implemented the function labtext() as a member of the class Labeltext. You have implemented it as a standalone function inside a cpp file. Your linker is complaining that it can't find Labeltext::labtext() because in fact you declared it in the header, but didn't implement it.

I think you need to learn how to walk in C++ before you attempt to write code in C++ + Qt.

[parulkalra14]

ok i understand where i am going wrong...i replaced below code:
Labeltext::Labeltext(QFrame *parent) :QLabel(parent)
{

}

void labtext()
{
...
}

with

Labeltext::Labeltext(QFrame *parent) :QLabel(parent)
{

}

void Labeltext:: labtext()
{
QTextCursor cursor=QPlainTextEdit.textCursor();
if(cursor.block().text().contains("",Qt::CaseInsen sitive))
{
Qlabel->setText("");

}
}
Something is wrong with this highlighted line and i am not able to find and my appication is stopped working when i run it. Need help!!!

[anda_skoa]

What do you expect this line to do?

Do you have a member variable called QPlainTextEdit? Is its type a class that has a textCursor() method?


Cheers,
_

[parulkalra14]

I am declaring cursor variable and want to link cursor with plainTextEdit so that whenever cursor moves on a text, the label associated with that particular text will displayed on a Label Widget.

[sulliwk06]

This thread is killing me. You really need to take a class or read a book on C++.

"QPlainTextEdit.textCursor()" is calling the function textCursor on an object named QPlainTextEdit.
What you want is to call the function textCursor on an object of type QPlainTextEdit.

So you should have a QPlainTextEdit declared somewhere

QPlainTextEdit myPlainTextEdit;

QPlainTextEdit myPlainTextEdit;

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and then call textCursor on that

myPlainTextEdit.textCursor();

myPlainTextEdit.textCursor();

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