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[Atomic_Sheep]

I'm trying to understand why you can't do something like this:

#include <QtCore/QCoreApplication>
#include <QDebug>
 
//Global variable
int value(1);
 
qDebug() << value; //request for global variable
 
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
 
    int value(2); //local variable
 
    qDebug() << value; //request for local variable
    qDebug() << ::value; //request for global variable
 
    return a.exec();
}

#include <QtCore/QCoreApplication>
#include <QDebug>

//Global variable
int value(1);

qDebug() << value; //request for global variable

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    int value(2); //local variable

    qDebug() << value; //request for local variable
    qDebug() << ::value; //request for global variable

    return a.exec();
}

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I read that this is the way C++ was designed which is fair enough, I'm just trying to understand why it was done this way. Is it a Windows limitation? I'm guessing not. I'm not really familiar with scripting languages. I did pearl a long time ago for a class but that was it, don't remember anything about it. So Perl works under Windows doesn't it?

[anda_skoa]

Line 7 doesn't work because qDebug() << is code that needs to be executed, so it needs to be on an execution code path.

For the variable name hiding: usually it is a bad idea to have local names that hide names on a more wider scope, for global or member variables that is usually solved by marking them explicitly as such.

E.g.

class Foo {
private:
    int m_value; // using m_ prefix to say this is a member variable
};

class Foo {
private:
    int m_value; // using m_ prefix to say this is a member variable
};

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If you really need a global variable with such a common names as "value" you can put it into a namespace, e.g.

namespace {
    int value; // access through ::value
}
namespace globalvalues {
    int value; // access through globalvalues::value
}

namespace {
    int value; // access through ::value
}
namespace globalvalues {
    int value; // access through globalvalues::value
}

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Cheers,
_