How to use an external variable ?

[Santosh Reddy]

both "alternate defintion 1" and "alternate defintion 2" are ok, either one of these will work, you should be getting the qDebug() messages, Under Windows, the message is sent to the console, if it is a console application; otherwise, it is sent to the debugger. (check "Application Ouput" tab is using Qt Creator)

[Computer Hater]

both "alternate defintion 1" and "alternate defintion 2" are ok, either one of these will work, you should be getting the qDebug() messages, Under Windows, the message is sent to the console, if it is a console application; otherwise, it is sent to the debugger. (check "Application Ouput" tab is using Qt Creator)

The qDebug() output from the Dummy class functions is not showing in Application Output.
But when I use qDebug() from my main function, e.g. if I add a public QString to the Dummy class, set its value in the Dummy constructor and access and output it with qDebug() from 'main', then it works.
I forgot to mention that I had done this too.

You may wish to research singletons.

Well, I stumbled on this thread when posting this.
The singleton code looks a bit cumbersome to me. Does it have any intrinsic advantages or is it just a work-around to avoid global variables ? Are global variables just poorly implemented in C++ ?
I'd just like to understand why it's good to use singletons.

[Santosh Reddy]

does your .pro file anything more than this?

HEADERS += \
    data.h
 
SOURCES += \
    data.cpp \
    main.cpp

HEADERS += \
    data.h

SOURCES += \
    data.cpp \
    main.cpp

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[Computer Hater]

My project file looks like this:

#-------------------------------------------------
#
# Project created by QtCreator 2010-11-25T17:13:18
#
#-------------------------------------------------
 
QT       += core gui
 
TARGET = Test
TEMPLATE = app
 
 
SOURCES += main.cpp\
        mainwindow.cpp \
    data.cpp \
    ssvector.cpp
 
HEADERS  += mainwindow.h \
    data.h \
    ssvector.h
 
FORMS    += mainwindow.ui

#-------------------------------------------------
#
# Project created by QtCreator 2010-11-25T17:13:18
#
#-------------------------------------------------

QT       += core gui

TARGET = Test
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp \
    data.cpp \
    ssvector.cpp

HEADERS  += mainwindow.h \
    data.h \
    ssvector.h

FORMS    += mainwindow.ui

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For the current test I've outcommented all calls to mainwindow and ssvector (in the source code), as they were from earlier tests and were only still in there for later use.

[Santosh Reddy]

test with the .pro file posted my me...