Why are pointer objects created while defining a class?

[Swati777999]

Hi All,
I hope that you're doing well .I've a doubt regarding the creation of pointer object of a class. I want to know why are pointer objects created in the definition of a class instead of simply creating an object of that class.

[JKSH]

@Swati777999 said in Why are pointer objects created while defining a class?:

I want to know why are pointer objects created in the definition of a class instead of simply creating an object of that class.

There can be multiple different reasons. Some reasons are:

1. To save space. The size of a pointer is always 32 bits or 64 bits (4 bytes or 8 bytes) on today's common PCs, but the size of a class/struct depends on the sizes of all its members. If an object is too big, it cannot be created on the stack (or it becomes easier to trigger a stack overflow).
2. Because some objects cannot be copied. For example, you cannot have QList<QWidget>; you must use QList<QWidget*>
3. Because of style/convention. Qt uses pointers to show that an object is an Identity object, and it uses non-pointers to show that an object is a Value object: https://doc.qt.io/qt-6/object.html#qt-objects-identity-vs-value