Constructor of every object in vector is called everytime I add a new element. How do I resolve this?

Question

I made a vector to hold the dynamic (user determined) number of objects of a class that will be created during runtime. However, every time I use the "push_back" function to add another object to the vector, the constructor of every single object in the vector is called. I suspect it's because new memory has to be allocated every addition, so I could use reserve function, but I then can't exceed that amount

Answer 1

I think I have a solution to your problem. Your vector should be object pointers like this:

std::vector<MyClass*> objectPointerVector;

Next, you can create a dynamic amount of objects like this:

std::cout << "Enter number of objects to create: ";
std::cin >> nObjects;

for (int i = 0; i < nObjects; i++) {
objectPointerVector.push_back(new MyClass());
}

Just remember you HAVE to delete the memory when you are done with the objects or your program. Here is how you do that:

std::vector<MyClass*>::iterator iter;
for (iter = objectPointerVector.begin(); iter != objectPointerVector.end(); iter++) {
delete (*iter);
}

There are many other ways to go about this and tons of discussions about it on the internet; it just depends on what you are using it for. I hope this helps! Happy coding :)

**EDIT**
There is a much easier way to do this that takes advantage of the vector's ability to call destructor functions automatically, so you don't have to manually delete them:

std::vector<MyClass> objectVector;
cin >> nObjects;
objectVector.resize(nObjects); // http://www.cplusplus.com/reference/vector/vector/resize/

// then you can call each object like this
objectVector[n].objectFunction();

The destructors will be called when the end of the vector's scope has been reached, freeing up the memory.