Question

Sorry for two questions in succession.

I would like to declare a vector of an Object as instance data then initialize its size in a constructor, as such:

  class Test
    {
    private:
        std::vector<Object_I_madeup> myVector;
        int n;
    public:
         Test(int n):
           n(n)
        {
            myVector(n); //Intending to set the size of the vector to n entries
        }

I tried to find a .setSize() a la Java, and doubt I should use resize(). I know this isa simple question – but what is the best way to do this?

Thanks

Answer 1

Add it to your initializers:

Test (int n):
    myVector(n), n(n) {}

Take note that it should be placed before n because the members get initialized in the order they appear in your class. As well, if all your n member does is keep track of the size of the vector, you might as well just use myVector.size() instead. You should also be a bit more rigorous with invalid values, as here, someone could pass -5 or something of the sort and you wouldn’t stop them. I realize this is a test, but realize an unsigned parameter would be better. As Ed points out, using size_t is your best option because that’s the equivalent of what the vector uses for its size (std::vector<T>::size_type).