Question

I want to be sure that no memory leak takes place.

   struct tStruct{
       uint32_t id;
       A* a;
       C b;
   };
   std::vector<tStruct*> m_vector;

I push and erase objects into vector following way.

Pushing :

tStruct* myStruct = new tStruct;
myStruct->id = ID; // Some unique value
myStruct->a= new A();
myStruct->b = c; // c is an object
m_vector.push_back(myStruct);

Erasing :

 // Some stuff here 
 for (uint32_t i = 0; i < m_vector.size(); i++) {
     if (m_vector.at(i)->id == ID) { // Some filtering
         delete m_vector.at(i);
         m_vector.erase(m_vector.begin() + i);
     }
 }

Do i understand correctly that

1. I need to delete myStruct->a explicitely as it is alloced in heap ?
2. For the other members, they will be deleted automatically as they are in stack.

Answer 1

You need to manually delete all dynamically allocated objects which are created by new operator. Otherwise you have potential memory leak, as you haven’t deleted A* a;

new and delete, new [] and delete [] should always be used in pair.

Better solution is to use smart pointers:

struct tStruct
{
     uint32_t id;
     std::unique_ptr<A> a;
     C b;
};

std::vector<std::unique_ptr<tStruct>> m_vector;

Use erase remove idiom to remove items from vector:

m_vector.erase(std::remove_if(m_vector.begin(), m_vector.end(), 
               [](std::unique_ptr<tStruct>& up){ return up->id == ID; }), 
               m_vector.end());