“调用隐式删除的默认构造函数”错误

Question

我不断收到三个错误，这些错误都与“调用____的隐式删除的默认构造函数有关。有人碰巧知道这是为什么吗？

/Users/vivekreddy/Desktop/Vivek/School/Spring 2016/CS32/project 3/project 3/Player.cpp:114:18：调用“BadPlayerImpl”的隐式删除的默认构造函数

#include "provided.h"
#include <iostream>
#include <string>
using namespace std;

class HumanPlayerImpl:public Player
{
  public:
    virtual bool isInteractive() const { return true;};
    int chooseMove(const Scaffold& s, int N, int color);

};

class BadPlayerImpl: public Player
{
  public:
    int chooseMove(const Scaffold& s, int N, int color);
};

class SmartPlayerImpl: public Player
{
  public:
    virtual bool isInteractive() const { return true;};
    int chooseMove(const Scaffold& s, int N, int color);
};

//implementations

//put virtual in front of implementations only or declarations here as well?

int HumanPlayerImpl::chooseMove(const Scaffold& s, int N, int color)  //goal is to get N in a row, return the column necessary to put the checker so we could do that.  otherwise return -1.  can make the column be arbitrary
{
    //algorithm is inputting N so maybe don't need this check?
    if (N>s.cols()||N<=0) {
        cout<<"Enter a number within the valid range of columns you specified";
        return -1;
    }

    if(s.numberEmpty()==0)
    {
        return -1;
    }

    int columnnum;
    while (columnnum<=s.cols()||columnnum<=0) {
        cout<<"Enter column number of your move";
        cin>>columnnum;
        if (columnnum<=s.cols()) {
            return columnnum;
        }
        cout<<"Column number not valid ";
    }
    return -1; //OK?
}

int BadPlayerImpl::chooseMove(const Scaffold& s, int N, int color)
{
    if ((N>=s.cols()&&N>=s.levels())||N<=0) { //make sure this works
        cout<<"Enter a number within the valid range of columns you specified";
        return -1;
    }
    for (int j=0; j<s.cols();j++) {
        if (s.checkerAt(j,0)==VACANT) {
            return j;
        }
    }
    return -1; //see if this OK
}

int SmartPlayerImpl::chooseMove(const Scaffold& s, int N, int color)
{
    return -1;  //  This is not always correct; it's just here to compile
}

//******************** Player derived class functions *************************

// These functions simply delegate to the Impl classes' functions.
// You probably don't want to change any of this code.

HumanPlayer::HumanPlayer(string nm)
 : Player(nm)
{
    m_impl = new HumanPlayerImpl;  //error is here
}

HumanPlayer::~HumanPlayer()
{
    delete m_impl;
}

int HumanPlayer::chooseMove(const Scaffold& s, int N, int color)
{
    return m_impl->chooseMove(s, N, color);
}

BadPlayer::BadPlayer(string nm)
 : Player(nm)
{
    m_impl = new BadPlayerImpl;  //error is here
}

BadPlayer::~BadPlayer()
{
    delete m_impl;
}

int BadPlayer::chooseMove(const Scaffold& s, int N, int color)
{
    return m_impl->chooseMove(s, N, color);
}

SmartPlayer::SmartPlayer(string nm)
 : Player(nm)
{
    m_impl = new SmartPlayerImpl;  //error is here
}

SmartPlayer::~SmartPlayer()
{
    delete m_impl;
}

int SmartPlayer::chooseMove(const Scaffold& s, int N, int color)
{
    return m_impl->chooseMove(s, N, color);
}

下面是我对作为基类的 Player 类的声明：

 class Player
{
  public:
    Player(std::string nm) : m_name(nm) {}
    virtual ~Player() {};
    std::string name() const { return m_name; };
    virtual bool isInteractive() const { return false; }
    virtual int chooseMove(const Scaffold& s, int N, int color) = 0;
      // We prevent any kind of Player object from being copied or assigned by
      // making the copy constructor and assignment operator unavailable in
      // the base class (and thus in any derived class).
    Player(const Player& other) = delete;
    Player& operator=(const Player& other) = delete;
  private:
    std::string m_name;
};

原文由 Vivek Reddy 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

因为您在基类中声明了一个构造函数，特别是 Player::Player(std::string nm) ，所以编译器不可能为您的子类提供一个隐式默认构造函数作为您的父类 Player 不能默认构造在首位。

在您的子类中提供构造函数或继承基类 (C++11) 的构造函数。例如：

 BadPlayerImpl::BadPlayerImpl(std:string nm)
  : Player(nm)
{
   ...
}

原文由 Sebastian Hoffmann 发布，翻译遵循 CC BY-SA 3.0 许可协议