CODEWITHSUNDEEP
c++
Oana Furtună
Oana Furtună

Reputation: 23

Delete a class object in C++

I'm doing a simple Zombie island game in the console and I'm trying to make the zombies die when the human lands on them.

To create the zombies I used my Zombie class like this:

Zombies *zombie = new Zombies[4];

To check if the human and the zombie are on the same place I used a simple for loop:

int zombieCount = 4;
for (int i = 0; i < 4; i++)
{
    if (player.getPosX() == zombie[i].getPosX() && player.getPosY() == zombie[i].getPosY())
    {
        zombieCount--;

    }
}

Besides decreasing the zombieCount, the zombie I hit should disappear from the game. How do I do that?

Upvotes: 1

Views: 248

Answers (4)

Felix
Felix

Reputation: 31

In C++11, you can use std::remove(first, last, value) to remove certain elements in an array. The function returns the new array ending, e.g. use:

auto end = std::remove(std::begin(zombie), std::end(zombie), zombie[i]);

I'd suggest to use std::vector which is a dynamic array which suits more your needs.

References: std::remove and std::vector.

Suggested std::vector example:

std::vector<Zombies> zombies;
// init with zombies.push_back(someZombie);

for (vector<Zombies>::iterator it = zombies.begin(); it != zombies.end(); /*no ++it*/) {
  if (player.getPosX() == it->getPosX() && player.getPosY() == it->getPosY())
      it = zombies.erase(it);
  else 
      ++it;
}

int zombieCount = zombies.size();

Upvotes: 2

em2er
em2er

Reputation: 881

You can use std::erase-remove_if with lambda as in following one-liner:

zombies.erase(std::remove_if(zombies.begin(), zombies.end(),
                  [& player](const Zombie& z){return player.getPosX() == z.getPosX() && player.getPosY() == z.getPosY();}),
              zombies.end());

Supposed you have a vector<Zombie> zombies or list<Zombie> or another container that can be reordered.

Upvotes: 1

Aconcagua
Aconcagua

Reputation: 25516

NathanOliver recommended in a comment to use std::remove_if - in my eyes best of the so far proposed solutions, unfortunately it is just a comment, so I illustrate here how it could look like (a little shortened by just comparing the X-coordinate...):

Person p;
std::vector<Zombie> zombies(4);
auto end = std::remove_if
    (
        zombies.begin(), zombies.end(),
        [&p](Zombie const& zombie) { return (zombie.getPosX() == p.getPosX()) && (zombie.getPosY() == p.getPosY()); }
    );
zombies.erase(end, zombies.end());

Upvotes: 0

Rama
Rama

Reputation: 3305

Use a vector container:

Zombies zombieModel;

std::vector<Zombies> zombieVec(10, zombieModel);

int zombieCount = zombieVec.size();
for (int i = 0; i < zombieVec.size(); i++)
{
    if (player.getPosX() == zombieVec[i].getPosX() && player.getPosY() == zombieVec[i].getPosY())
    {
        zombieCount--;
        zombieVec.erase(zombieVec.begin()+i);
        i--;
    }
}

Upvotes: 0

Related Questions