QSet with a Custom Class

MDCato

I was looking for a very simple example of a Custom Class being used in a QSet, and I could not find one anywhere.

I have eventually worked out this example, and I wanted to share with everyone, and also get feedback in case I did something wrong.

myclass.h

#ifndef MYCLASS_H
#define MYCLASS_H

#include <QObject>
#include <QDebug>

class MyClass
{
public:
    MyClass();
    MyClass(const MyClass &other);
    MyClass &operator=(const MyClass &other);
    bool operator==(const MyClass &other) const;

    QString alpha;
    QString beta;
};

inline uint qHash(const MyClass &key, uint seed){
    return qHash(key.alpha, seed) ^ qHash(key.beta, seed+1);
}

QDebug operator<<(QDebug dbg, const MyClass &data);
#endif // MYCLASS_H

myclass.cpp

#include "myclass.h"

MyClass::MyClass(){

}

MyClass::MyClass(const MyClass &other){
    alpha = other.alpha;
    beta = other.beta;
}

MyClass& MyClass::operator=(const MyClass &other){
    MyClass *ret = new MyClass();
    ret->alpha = other.alpha;
    ret->beta = other.beta;
    return *ret;
}

bool MyClass::operator==(const MyClass &other) const{
    return alpha.compare(other.alpha) == 0 && beta.compare(other.beta) == 0;
}

QDebug operator<<(QDebug dbg, const MyClass &data){
    dbg.nospace() << "MyClass(" << data.alpha << ", " << data.beta << ")";
    return dbg.maybeSpace();
}

main.cpp

#include <QCoreApplication>
#include <QTimer>
#include <QDebug>

#include "myclass.h"

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

    MyClass a;
    MyClass b;

    a.alpha = QString("Hello");
    a.beta = QString("World");
    b.alpha = QString("foo");
    b.beta = QString("bar");

    QSet<MyClass> set;
    set.insert(a);
    set.insert(b);

    qDebug() << set;

    QTimer::singleShot(250, &app, &QCoreApplication::quit);
    return app.exec();
}

output looks like this:

QSet(MyClass("foo", "bar"), MyClass("Hello", "World"))
Press <RETURN> to close this window...

dheerendra

Thanks sharing this example. We appreciate your effort. It helps others as well. Enjoy Qt Programming.