Question

If I have a STL container that takes object pointers as elements, I will need to delete the pointers in the destructor of the class that has such a container. Since the operation of deleting a pointer

delete ptr_; 
ptr_ = 0;

might be often used, I wonder if there is a function (or function object) template that does this, defined in boost, or STL or by the standard somewhere as the function object DeletePointer defined in the following example:

#include <list>
#include <algorithm>

template<class Pointer>
class DeletePointer
{
    public: 
        void operator()(Pointer t)
        {
            delete t; 
            t = 0;
        }
};

using namespace std;

int main()
{
    list<double*> doublePtrList;

    doublePtrList.push_back(new double (0));
    doublePtrList.push_back(new double (1));
    doublePtrList.push_back(new double (2));
    doublePtrList.push_back(new double (3));

    for_each(doublePtrList.begin(), doublePtrList.end(), DeletePointer<double*>());
};

Answer 1

If (for some reason) you can’t store smart pointers instead of raw pointers in your collection, consider using a Boost pointer container instead.