CODEWITHSUNDEEP
c++listiterator
A.Pope
A.Pope

Reputation: 23

Why does list.end() not change when new item is added?

I am working on a programm which has two lists. One of the list stores objects. The other list stores pointers to items of the list containing the objects. When a new item is added to the object list I want to get the pointer to the object. But I always get the same pointer returned.

Since my program is to big now I made a new, smaller one to show you the problem:

#include <iostream>
#include <list>

using namespace std;

class C_Test
{
    public:
        int a;
};

int main()
{
    std::list<class C_Test> Testlist;
    C_Test A;
    C_Test B;
    Testlist.push_back(A);
    C_Test * p = &*Testlist.end();
    cout << p << endl;
    Testlist.push_back(B);
    p = &*Testlist.end();
    cout << p;  
}

Result:

0x22fe20
0x22fe20

I would expect the programm to print out two different pointers since the end of list should have changed? Why does it give me two times the same pointer?

I really would appreciate your help in this matter.

Upvotes: 0

Views: 146

Answers (1)

Vlad from Moscow
Vlad from Moscow

Reputation: 310930

For starters dereferencing the iterator returned by the member function end has undefined behavior.

I think you mean

 C_Test * p = &Testlist.back();

Upvotes: 3

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