Question

I’m new to C++ so this is probably a very simple question, but I haven’t been able to find any examples online that have helped.

I’ve defined my own Bubble class and I need to create a vector/list (I’m used to C# and Java, so I’m not sure which is correct) to dynamically store Bubble objects in. Here’s my code so far:

#include "Bubble.h"
#include <vector>
#include <list>

int backgroundImages[10]; 
list<Bubble> bubbles;
vector<Bubble> bubbles_two;
Bubble b;

void AppMain()
{
    loadImages();
    ViewAdd(backgroundImages[8], 0,0);
    b = Bubble();
    b.velocity = Vector2D(9,4);

    //I know this can't be right..
    bubbles.add(b);
    bubbles_two.add(b);
}

Neither the list nor the vector works – it says “list/vector is not a template” in my error list.

Which should I use, list or vector? And how do I correctly implement it?

Answer 1

The functions vector.add() and list.add() do not exist.

#include "Bubble.h"
#include <vector>
#include <list>

int backgroundImages[10]; 
std::list<Bubble> bubbles(); // use the std namespace and instantiate it
std::vector<Bubble> bubbles_two(); // same here
Bubble b;

void AppMain()
{
    loadImages();
    ViewAdd(backgroundImages[8], 0,0);
    b = Bubble();
    b.velocity = Vector2D(9,4);

    //I know this can't be right..
    bubbles.push_back(b); // std::list also defines the method push_front
    bubbles_two.push_back(b);
}

There are almost no obvious differences between the vector and the list, but functionally, there are.

Compared to the other base standard
sequence containers (deques and
lists), vectors are generally the most
efficient in time for accessing
elements and to add or remove elements
from the end of the sequence. For
operations that involve inserting or
removing elements at positions other
than the end, they perform worse than
deques and lists, and have less
consistent iterators and references
than lists.

Compared to other base standard
sequence containers (vectors and
deques), lists perform generally
better in inserting, extracting and
moving elements in any position within
the container, and therefore also in
algorithms that make intensive use of
these, like sorting algorithms.