Does vector::erase() on a vector of object pointers destroy the object itself?

Question

I have a vector of pointers to objects. I need to remove an element from the vector and place that element in another list.

I read that erase can be used to remove the object from the vector, but I also read that it calls the objects destructor before doing so.

I need to know whether or not erasing the object will destroy it as well.

Answer 1

vector::erase
Removes from the vector container and calls its destructor but If the contained object is a pointer it doesnt take ownership of destroying it.

You will have to explicitly call delete on each contained pointer to delete the content it is pointing to, for example:

void clearVectorContents( std::vector <YourClass*> & a )  {         for ( int i = 0; i < a.size(); i++ )      {                delete a[i];         }         a.clear();  }  

Storing raw pointers in standard containers is not a good idea. If you really need to store resources that have to be allocated by new, then you should use boost::shared_ptr. Check out the Boost documentation.

An more generic & elegant solution:
This solution makes use of for_each & templates as @Billy pointed out in comments:

// Functor for deleting pointers in vector. template<class T> class DeleteVector {     public:     // Overloaded () operator.     // This will be called by for_each() function.     bool operator()(T x) const     {         // Delete pointer.         delete x;         return true;     } }; 

And this can be called as:

for_each( myclassVector.begin(),myclassVector.end(),           DeleteVector<myclass*>()); 

where, myclassVector is your vector containing pointers to myclass class objects.

Usage Example:

#include "functional" #include "vector" #include "algorithm" #include "iostream"  //Your class class myclass {     public:         int i;         myclass():i(10){} };   // Functor for deleting pointers in vector. template<class T> class DeleteVector {     public:     // Overloaded () operator.     // This will be called by for_each() function.     bool operator()(T x) const     {         // Delete pointer.         delete x;         return true;     } };   int main() {     // Add 10 objects to the vector.     std::vector<myclass*> myclassVector;      for( int Index = 0; Index < 10; ++Index )     {         myclassVector.push_back( new myclass);     }      for (int i=0; i<myclassVector.size(); i++)      {         std::cout << " " << (myclassVector[i])->i;     }      // Now delete the vector contents in a single  line.     for_each( myclassVector.begin(),               myclassVector.end(),               DeleteVector<myclass*>());      //Clear the vector      myclassVector.clear();      std::cout<<"\n"<<myclassVector.size();      return 0; }