How to check object is valid.

[Taz742]

Hello.
I have my class object, if i have this object on the different places and when i deleted and initialized this object to NULL i want this object would be NULL on all the other places. It is possible?

#include "mainwindow.h"
#include <QApplication>
#include "QDebug"

class A {
    public:
        int x;
        int y;
};

class B : public A {
    public:
        B(int a, int b) {
            this->m = a;
            this->n = b;
        }

        int m;
        int n;
};

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

    B* temp = new B(1, 2);
    B* b1 = temp;
    B* b2 = temp;

    delete temp;
    temp = NULL;

    qDebug() << b1->x << b2->x; //its print 421312312 -2131231231

    return a.exec();
}

[Taz742]

am using QSharedPointer.

        QSharedPointer<B> obj = QSharedPointer<B>(new B(1, 2));

        obj.clear();

        B* t = obj.data();

        if (t)
            qDebug() << t->m << t->n;
        else {
            qDebug() << "NULL";
        }

[Taz742]

am using QSharedPointer.

        QSharedPointer<B> obj = QSharedPointer<B>(new B(1, 2));

        obj.clear();

        B* t = obj.data();

        if (t)
            qDebug() << t->m << t->n;
        else {
            qDebug() << "NULL";
        }

[jsulm]

@Taz742 said in How to check object is valid.:

qDebug() << b1->x << b2->x; //its print 421312312 -2131231231

Yes, it prints garbage because nobody initialises x.