Question

I am writing for platform that does not have build in STL but do have templates support

I am working on my own std::vector implementation.

template<typename T> class Array
{
private:
    T * buffer;
    int count;
    int capacity;
public:
    Array() : buffer(0), count(0), capacit(0) { }
    ~Array() { if(buffer) delete[] buffer; }
    void IN_ANY Reserve(const int capacity)
    {
        if(capacity >= count)
        {
            T * newBuff = new T[capacity];
            if(capacity > count)
                memset(newBuff+count, 0, (capacity-count) * sizeof(T));
            memcpy(newBuff, buffer, count * sizeof(T));

            if(buffer)
                delete [] buffer;

            buffer = newBuff;
            this->capacity = capacity;
        }
    }
    // Other methods...
}

The problem comes when T has non-trival constructor, non-trival destruction and overloaded operator=. Then, when Reserving additional memory for array, destructors for T will be called, and than constructors. But not copy constructor (since I used memcpy). How could I improve Reserve method?

Answer 1

The answer I was looking for was placement new