Question

#include <vector>

int main()
{
   vector <class> abc;
}

when pressing some key

vector.push_back(class());

each loop

draw(vector)// what should the parameters be?

draw function

draw(vector,sizeofvector)
{
    for (int x=0;x< sizeofvector;x++)
    {draw vector[x];}
}

how should the parameters look? should i be passing an *abc?

Answer 1

If you don’t intend to modify the vector, you usually pass it by const reference.

void draw(const std::vector<T>& v)
{
    for (int x = 0; x < v.size(); x++)
    {
        // draw v[x];
    }
}

You can also use iterators (this is often preferable).

void draw(const std::vector<T>& v)
{
    for (std::vector<T>::const_iterator x = v.begin(); x != v.end(); ++x)
    {
        // draw *x;
    }
}

The reason you don’t pass it by value (draw(std::vector<T> v)) is because that would cause the entire vector to be copied every time you call the function, which is obviously incredibly inefficient. References mean that you just refer to the existing vector rather than creating a new one.