Is it possible to create a vector of pointers?

user98188 picture user98188 · May 3, 2009 · Viewed 27.5k times · Source

Just wondering, because of a problem I am running into, is it possible to create a vector of pointers? And if so, how? Specifically concerning using iterators and .begin() with it, ie: How would I turn this vector into a vector of pointers:

class c
{
     void virtual func();
};

class sc:public c
{
     void func(){cout<<"using func";}
};

sc cobj;

vector<c>cvect
cvect.push_back(cobj);
vector<c>::iterator citer

for(citer=cvect.begin();citer<cvect.end();citer++)
{
     citer->func();
}

Answer

Logan Capaldo picture Logan Capaldo · May 3, 2009

Sure.

vector<c*> cvect;
cvect.push_back(new sc);
vector<c*>::iterator citer;
for(citer=cvect.begin(); citer != cvect.end(); citer++) {
  (*citer)->func();
}

Things to keep in mind:

You'll need to cleanup after your self if you use dynamically allocated memory as I did in my example

e.g.:

 for(...) { delete *i; }

This can be simplified by using a vector of shared_ptrs (like boost::shared_ptr). Do not attempt to use std::auto_ptr for this, it will not work (won't even compile).

Another thing to keep in mind, you should avoid using < to compare iterators in your loop when possible, it will only work for iterators that model a random access iterator, which means you can't change out your code to use e.g. a std::list.