If I append an item to a QList can I still change it?

kitfox

In the following code, when I call s.foo = 7;, will this modify the value in the list? I'd like to be able to allocate an object on the list and then be able to manipulate it via a reference, but am not sure of the most efficient way to go about this.

struct MyObj
{
    int foo = 0;
}

void testListAdd()
{
    MyStruct s;
    QList<MyStruct> list;
    list.append(s);
    s.foo = 7;
}

SGaist

Hi,

In this case, since you have 1 element in your list:

list[0].foo = 7;

kitfox

What if I wanted to say 'append a new element and set the new last element'.

SGaist

I'm not sure I'm following you, do you mean:

list.last().foo = 7;

?

kitfox

As I understand it, that will set the last element currently in the list. I want to append a new element and then set that.

SGaist

Can you show what you have in mind with some code.

list.last will return a reference to the last item of the list, so if you call append and then last, you'll get the latest inserted element in the list.

JonB

@kitfox

What if I wanted to say 'append a new element and set the new last element'.
As I understand it, that will set the last element currently in the list. I want to append a new element and then set that.

The code you showed already does just this. Since the signature is void QList::append(const T &value), what it appends is a reference, so changing the original item once it is in the list does change what is in the list. Is that what you were asking?

kitfox

@JonB Yes, that is what I wanted to know, JonB. Thanks..

Pablo J. Rogina

@kitfox if your issue is solved, please don't forget to mark your post as such. Thanks