c++ list, push_back, & templates?

Question

I am having a very difficult time using push_back on a template object. Can anyone explain why this works

    list<int> mylist;
    int myInt;
    mylist.push_back(myInt);

but this won't.

    list<KeyValuePair<T>> mylist;
    int myInt;
    mylist.push_back(myInt);

What do you expect the latter code to do? – GManNickG Jun 23 '17 at 22:28 — GManNickG, Jun 23 '17 at 22:28
KeyValurPair id a C# class, use std::pair – lapinozz Jun 23 '17 at 22:29 — lapinozz, Jun 23 '17 at 22:29

score 3 · Accepted Answer · answered Jun 23 '17 at 22:40

A list is a list of some templated objects. You instantiate a list of int objects with:

list<int> mylist;

This list now 'knows' it will be managing int objects.

One of the list methods is push_back() wich adds objects of the templated object type to the end of the list.

You instantiate a list of KeyValuePair objects with:

list<KeyValuePair<T>> mylist;

This second list is for managing KeyValuePair objects

Now if you try to add int objects to a list of KeyValuePair objects, this will fail because this list is a list of KeyValuePair objects, not int objects.

score 0 · Answer 2 · answered Jun 23 '17 at 22:31

0

The second list is declared to store object of type KeyValuePair<T>. Thats why its not allowing your to push_back() of type int.

answered Jun 23 '17 at 22:31

MKR

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c++ list, push_back, & templates?

2 Answers2