洗掉期間的分段錯誤[]-有解無憂

我正在構建一個游戲，每次創建一個玩家時，我都需要將一個玩家存盤在一個動態陣列中。我構建了一小段代碼來嘗試它，segmentation fault當我嘗試delete在桌子上插入第三個玩家時，我得到了一個。我只是無法意識到為什么會發生這種情況：header檔案是：

    #include <iostream>
    #include <string>
    #include <vector>
    
    using namespace std;
    
    class Player

{

    private:
        string PlayerName;
        int PlayerScore;
    public:
        Player();       
        Player(string name, int s);     
        ~Player() {};       
        string getPlayerName()  {return PlayerName;}
        int getPlayerScore() {return PlayerScore;}
        void setPlayerName(string name){PlayerName = name;}
        void setPlayerScore(int score){PlayerScore = score;}
};

class Game
{

    private:
        Player NewPlayer;
        int NPlayers;
        Player* PlayerList;
        //vector <Player> PlayerList2;
    
        
    public:
        Game();
        ~Game();
        void setNewPlayer(string, int); 
        void resizePlayerList();
        void PrintList();   
};

class檔案：

#include <iostream>
#include <string>
#include <cstring>
#include <memory>
#include "I.h"

using namespace std;


    
Player::Player()
{
    PlayerName = "";
    PlayerScore = 0;
}

Player::Player(string name, int s)
{
    PlayerName = name;
    PlayerScore = s;
}       


Game::Game() 
{
    NPlayers = 0;
    PlayerList = NULL;
};
Game::~Game() {};

void Game::setNewPlayer(string str, int scr)
{
    NewPlayer = Player(str, scr);   
    resizePlayerList(); 
    PrintList();        
}


void Game::resizePlayerList() {
   
    if(NewPlayer.getPlayerName() != "No Name")
    {
            int newSize = NPlayers  1;
            
            Player* newArr = NULL;
            newArr = new Player[newSize];           
            memcpy( newArr, PlayerList, NPlayers * sizeof(Player) );            
            NPlayers = newSize;         
            delete [] PlayerList;           
            PlayerList = newArr;            
            PlayerList[NPlayers-1] = NewPlayer;
    } 
   
}


void Game::PrintList()
{
    Player player;
    //cout << NPlayers << endl;
    for(int i= 0; i < NPlayers; i  )
    {
        player = PlayerList[i];     
        cout << player.getPlayerName() << " " <<  player.getPlayerScore() << endl;  
    }

}

main: _

#include <iostream>
#include <string>
#include "I.h"

using namespace std;

int main()
{
    Game NewGame;
    NewGame.setNewPlayer("Peter",20);
    NewGame.setNewPlayer("Someone Someone",30);
    NewGame.setNewPlayer("Someone else",40);
    return 0;
}

uj5u.com熱心網友回復：

問題源于這里：

memcpy(newArr, PlayerList, NPlayers * sizeof(Player));

你不能以這種方式復制類，除非它們是Trivially Copyable（最初是說POD，但正如 Yksisarvinen 在評論中指出的那樣，memcpy并沒有那么嚴格）。您可以通過使用回圈復制資料來解決此問題：

for (int i = 0; i < NPlayers;   i) {
    newArr[i] = std::move(PlayerList[i]);
}

不過，更好的選擇是使用 a std::vector<Player>，那么整個 resize 函式可以簡化為：

void Game::resizePlayerList() {
    if (NewPlayer.getPlayerName() != "No Name") {
        PlayerList.push_back(std::move(NewPlayer));
    }
}

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標籤：C c 11

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