访问冲突读取位置0xCCCCCCCC.using布尔值和无符号短值

Question

我试着像平常一样整洁地设置我的代码，但现在我在运行时遇到了这个错误

First-chance exception at 0x01313D46 in Server.exe: 0xC0000005: Access violation reading location 0xCCCCCCCC.

Visual studio还在“本地变量”框中告诉我，它无法读取

unsigned short port
bool listening

下面是出现错误的头部和Cpp

#pragma once

#include <SFML\Network.hpp>
#include <iostream>
using namespace std;

class NetServer
{
private:
    bool listening;
    unsigned short port;
public:
    NetServer(void);
    ~NetServer(void);

    void InitNetServer();

    void SetListening(bool a)
    {
        a = listening;
    }
    bool IsListening()
    {
        return listening;
    }

    void SetPort(unsigned short a)
    {
        a = port;
    }
    int GetPort()
    {
        return port;
    }
};

当调试器的SetListening(bool a)太大时，它就会中断，如果我把它去掉，它就会在SetPort处中断

这是我的Cpp

#include "NetServer.h"

sf::TcpListener listener;
sf::TcpSocket client;

NetServer::NetServer(void)
{
    //listener.listen(21025);
    //cout << "listening" << endl;
    while (true)
    {
        if (listener.accept(client) == sf::Socket::Done)
        {
            cout << "New connection received from " << client.getRemoteAddress() << endl;
        }
    }
}

NetServer::~NetServer(void)
{
    SetPort(NULL);
    SetListening(false);
}

void NetServer::InitNetServer()
{
    cout << "Initialising the NetServer" << endl;
    SetListening(true);
    SetPort(45000);

    listener.listen(GetPort());
    cout << "NetServer Initialised : Listening on Port "<< GetPort() << endl;
}

这是我唯一的另一个类，在GameServer.h/cpp中也被称为

    #include "GameServer.h"

GameServer::GameServer()
{
    Run();
}

GameServer::~GameServer(void)
{
    DestroyNetServer();
    Exit();
}

void GameServer::Run()
{
    cout << "Initialising the engine." << endl;

    /* Initialise stuff here */
    _NetServer->InitNetServer();
    /* Finish initialisation */

    SetGameRunning(true);

    while(GetGameRunning() == true)
    {
        _NetServer;
    }
}

void GameServer::Exit()
{
    exit(0);
}

NetServer & GameServer::GetNetServer()
{
    if(_NetServer == 0) throw exception ("Null Game Server");
    return *_NetServer;
}

void GameServer::CreateNetServer()
{
    _NetServer = new NetServer();
}

void GameServer::DestroyNetServer()
{
    delete _NetServer;
}




#pragma once

#include "NetServer.h"

#include <iostream>
using namespace std;

class NetServer;

class GameServer
{
public:
    GameServer();
    ~GameServer(void);

    void Run();
    void Exit();

    void SetGameRunning(bool running)
    {
        gameRunning = running;
    }
    bool GetGameRunning()
    {
        return gameRunning;
    }

    void CreateNetServer();
    NetServer & GetNetServer();
    void DestroyNetServer();

private:
    bool gameRunning;

    NetServer * _NetServer;
};

Answer 1

Run在构造函数中被调用，没有人初始化_NetServer指针。因此，您正在尝试调用一个未初始化对象的方法。在调用Run()之前添加CreateNetServer

GameServer::GameServer()
{
  CreateNetServer()
  Run();
}

Answer 2

看起来你从来没有初始化过listening或port。即使你的setter方法也帮不了你，因为赋值是颠倒的(你给本地参数赋值，而不是把值复制给实例成员)。

例如：

void SetListening(bool a)
{
    a = listening;
}

应该是：

void SetListening(bool a)
{
    listening = a;
}

除了修复setter之外，要修复从不赋值listening或port值的问题，还需要在constructor initialization list中这样做

NetServer::NetServer(void)
  : listening(false)
  , port(0)
{
    //listener.listen(21025);
    //cout << "listening" << endl;
    while (true)
    {
        if (listener.accept(client) == sf::Socket::Done)
        {
            cout << "New connection received from " << client.getRemoteAddress() << endl;
        }
    }
}

此外，我甚至不知道这段代码的目的是什么，但它看起来是错误的：

while(GetGameRunning() == true)
{
    _NetServer;
}