[SOLVED] For Loop Misbehavior in C++ and Qt 6.2

For Loop Misbehavior in C++ and Qt 6.2

First of all i'm a complete beginner in C++ and Qt and i'm using Qt 6.2 and C++11. This is the code that i have problem with:

QSet<QList<QString>> listSet;
for(int i = 0; i < 10; i++)
{
    QList<QString> myList;
    for(int r = 0; r < 10; r++)
    {
        myList << "Item" + QString::number(r);
    }
    listSet.insert(myList);
}

qInfo() << listSet.count();

I was expecting that i would get the output of "10" but instead i got "1". I changed the code to this and it fixed the problem but i just can't wrap my head around it:

QSet<QList<QString>> listSet;
for(int i = 0; i < 10; i++)
{
    QList<QString> myList;
    myList << "default" + QString::number(i);
    for(int r = 0; r < 10; r++)
    {
        myList << "Item" + QString::number(r);
    }
    listSet.insert(myList);
}

qInfo() << listSet.count();

i want to know why C++ is behaving like this.

Solution

QSet is a collection of unique objects. The first code snipped produces 10 equal to each other myList objects. Thus, QSet gets only one unique myList object: qInfo() << listSet.count(); outputs 1.

The second snippet makes not equal myList objects, they differ by the first list items, and qInfo() << listSet.count(); outputs 10.