How in the World to use an object inside a vector

[dtaqee88]

Ok so I have looked all through my book and have not seen anywhere how to use an object within a vector. I've been making a simple game using classes for the last couple of days and have found that it would be much easier/faster to just use a vector for my objects instead of declaring 4 independent objects. e.g.:

GET_CLASS player1;
GET_CLASS player2;
GET_CLASS player3;
GET_CLASS player4;

where GET_CLASS is my class and the players are the objects.
Can anyone speak on how to declare an object within a vector? Thanks

[zb0S216C]

There's two ways to get an object from a std::vector:

• std::vector::at(). This obtains an object from a std::vector based on the index you give it.
• std::vector::operator[]. This also obtains an object from a std::vector based on the index you give it.

Here's some working examples:

struct Object
{
    Object(int V_ = 0) : X_(V_) { }
    Object(Object const &O_) : X_(O_.X_) { }
    int X_;
};

int main()
{
    std::vector<Object> Objects_;
    Objects_.push_back(10);
    Objects_.push_back(20);

    // Get the first object in the vector:
    Objects_.at(0u).X_ = /*...*/;

    // Get the second object in the vector:
    Objects_[1u].X_ = /*...*/;
}

The difference between the two is std::vector::at() provides bounds-checking, while std::vector::operator[] does not.

Also, you don't declare objects inside a std::vector: you add them with std::vector::push_back(), and remove them with std::vector::pop_back().

_Wazzak

[AbstractionAnon]

Does this help?

//  Declare the vector
vector<GET_CLASS> players;
//  Create an iterator to traverse the vector
vector<GET_CLASS>::iterator  iter;
bool end_of_game = false;

// Populate the vector
for (int i=0; i<4; i++)
{  //  Create a player
    GET_CLASS player;
    //  Set some player attributes here 
    //  Add the player to the vector
    players.push_back (player);
}

//  Now play the game
while (! end_of_game)
{  //  Iterate through the players
    for (iter=players.begin(); iter!=players.end(); iter++)
      iter->Do_Move ();
}

BTW, it seems a little weird to call your class GET_CLASS, wouldn't PLAYER make more sense?

[Athar]

@AbstractionAnon
That is incorrect. Where are you deleting the instance created in line 12 and why are you using new in the first place?

[AbstractionAnon]

Fair point. Edited the example.