玩家退出后向量超出范围

Question

I'm having a major issue that I've tried to circumvent for many days now, but I can't come up with a good enough solution to fix it.

The problem is in my client/server connection (specifically in the gameserver code), where when I log a player out and there are more than 1 players online, all players that has a higher index in the vector than the logged out player are now invalidated, thus crashing the server from the player vector being out of range.

I have tried to shorten the code, to only most relevant code for you to read easier. I cannot include all the networking code, as it would be too much of a mess

main.cpp

#include <iostream>
#include <vector>

int main() {
        Player* newplayer = new Player(username, world);
        //Push two players into the vector, size is 1 after 0, 1
        world->players.push_back(newplayer);
        world->players.push_back(newplayer);

        //Log out player at index 0, then log player at index 1 out.
        for (int i = 0; i < world->characters.size(); i++) {
            world->Logout(world->players[0]);
            world->Logout(world->players[1]);
        }
    }
}

World.h/world.cpp

//in world.h
std::vector<Player*> players;

//in world.cpp
void World::Logout(Player* player)
{
    world->Logout(world->players[0]);this->Logout(player->character);

    this->players.erase(
        std::remove(UTIL_RANGE(this->players), player),
        this->players.end()
    );
}

I don't know if I have explained myself properly, so please if you have any feedback as to how I can re-formulate my question or specify more details, please do let me know.

Maybe, should I not use a vector at all? In this case, what do I need to use? My program is reliant on that the players still have the same "player id" throughout the program. If a player is removed, then that becomes a free element.

Eg if there are 10 players in the vector. {player, player, player, player, player, player, player, player, player, player} and player at index 0 logs out, it should look like this {null/free, player, player, player, player, player, player, player, player, player}

Answer 1

Your code has a problem. The docs say that std::remove will delete the element, and return a iterator. You are then erasing the iterator with std::vector::erase . However, the iterator returned from std::remove is past-the-end, thus causing a vector out-of-bounds error.