Removing a pointer from a std::vector without deleting the underlying object

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I have a pointer in my main function;

C++

Something* myptr = new Something();

I then add it a std::vector with push_back;

C++

std::vector<Something*> vec;
vec.push_back(myptr);

I then want to delete it from that vector without destroying it, because the main function still needs it. Essentially I'm removing one reference to it from the vector.

How can I achieve this?

What I have tried:

C++

vec.erase(std::remove(vec.begin(), vec.end(), myptr), vec.end());

C++

vec.erase(std::remove(vec.begin(), vec.end(), &myptr), vec.end());

C++

vec.erase(myptr);

C++

delete vec[myptr];

Posted 21-Jun-22 4:05am

sorauts

Updated 21-Jun-22 4:42am

v2

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CPallini · Accepted Answer · 2022-06-21T04:42:00

Solution 2

You could also use a std::shared_ptr, instead of a naked pointer.

Posted 21-Jun-22 4:42am

CPallini

Comments

Greg Utas 21-Jun-22 11:29am

5. And then the number of users of the pointer would be decremented when it was erased.

CPallini 21-Jun-22 13:01pm

Thank you.

steveb · Accepted Answer · 2022-06-21T04:21:00

Solution 1

Given your code above, this will remove an element from the vector which equals to your pointer without deleting is so to speak. The pointer itself must be deleted in a separate step.

C++

std::vector<Something*>::iterator it = std::find(vec.begin(), vec.end(), myptr);
if(it != vec.end())
   vec.erase(it);

Posted 21-Jun-22 4:21am

steveb

Updated 21-Jun-22 4:24am

v2

Comments

CPallini 21-Jun-22 10:41am

5.

sorauts 21-Jun-22 11:20am

Thank you - just needed an #include <algorithm> and it's working great