Question

我一直在为一款基于游戏机的游戏编写一些代码，其中包含玩家和一些敌人。到目前为止，我只为我的播放器类编写了一种方法。 player类是一个名为entity的父类的子类，它也有一个名为enemy的子类。在player.cpp的方法void player::takeInput()中，我尝试修改值this->xCoordinate，其中int xCoordinate是实体类的公共成员。每当我编译这段代码时，我都会收到错误：

include\entity.h line 31 error: 'int entity::xCoordinate' is inaccessible
C:\Users....\ line 72 error:  'error within this context'

请注意，在第72行，代码为：

int newX = this->xCoordinate;

对于我每次对this->xCoordinate或this->yCoordinate进行的所有其他（多次）调用重复此错误，其中包含entity.h第31行的错误以及错误：＆＃39;在此背景下的错误＆＃39;。

我认为这个错误与类如何从彼此继承有关。我能找到的唯一解决方案是解决会员被标记为私有的问题，因为我已将该会员标记为公开，因此不适用于此问题。

我不是一位经验丰富的程序员，只会将自己评为中级，所以如果代码中包含多个错误，请原谅代码！

提前感谢您的帮助！这是源代码，请注意我还没有对项目的其余部分做太多工作：

main.cpp中：

#include <iostream>
#include <stdlib.h>
#include "entity.h"
#include "player.h"
#include "enemy.h"
#include <vector>

using namespace std;

int playerX;
int playerY;
int noEnemies;

void initGrid()
{
    return;
}

void dispGrid()
{

    return;
}

int verifyMove(int x, int y)
{

    return 0;
}

void aiTurn()
{
    return;
}

int main()
{

    return 0;
}

entity.h：

#ifndef ENTITY_H
#define ENTITY_H
#include <iostream>
#include <vector>

using namespace std;
enum direction
{
    NORTH,
    SOUTH,
    EAST,
    WEST
};

enum weaponClass
{
    PISTOL,
    SWORD,
    RIFLE,
    SHOTGUN
};



class entity
{
    public:
        weaponClass currentWeapon;
        int health;
        int weaponStrength;
        int xCoordinate;
        int yCoordinate;
        string spritePath;
        string name;
    protected:

    private:
};

#endif // ENTITY_H

entity.cpp不包含任何代码，因为它没有方法。它仅用作enemy.h和player.h的分组。

player.h：

#ifndef PLAYER_H
#define PLAYER_H

#include "entity.h"
#include <iostream>



class player : public entity
{
    public:
        direction nextMoveDir;
        direction attackDir;
        int ammunition;
        player();
        virtual ~player();
        virtual void addToGrid();
        virtual void draw();
        void takeInput();
        void restoreHealth();
        void makeMove();
        int health;

    protected:

    private:
};

#endif // PLAYER_H

player.cpp :(对不起大量的代码！）

#include "player.h"
#include "entity.h"
#include "enemy.h"

#include <iostream>
#include <vector>

using namespace std;

player::player()
{
    //ctor
}

player::~player()
{
    //dtor
}

vector<enemy*> listOfEntities; 



void player::takeInput()
{
    cout << "Would you like to move (1), or attack (2)?" << endl;
    int input;
    cin >> input;
    if(input == 1)
    {
        bool cont = false;
        while(!cont)
        {
            cont = true;
            // Moving
            cout << "In which direction would you like to move:" << endl;
            cout << "1) North, 2) South, 3) East, 4) West." << endl;
            int newX = this->xCoordinate;
            int newY = this->yCoordinate;
            cin >> input;
            switch(input)
            {
            case 1:
                this->nextMoveDir = NORTH;
                newX++;
                break;
            case 2:
                this->nextMoveDir = SOUTH;
                newX--;
                break;
            case 3:
                this->nextMoveDir = EAST;
                newY++;
                break;
            case 4:
                this->nextMoveDir = WEST;
                newY--;
                break;
            default:
                cont = false;
                cout << "Invalid selection." << endl;
                break;

            }
            for(int i = 0; i < listOfEntities.size(); i++)
            {
                int itrX = listOfEntities[i]->xCoordinate;
                int itrY = listOfEntities[i]->yCoordinate;
                if(((newX == this->xCoordinate) && (newY = this->yCoordinate))) )
                {
                    // tile is occupied
                    cout << "That tile is occupied!" << endl;
                    cont = false;
                    break;
                }
            }
        }


    }
    else if(input == 2)
    {
        // Attacking
        bool cont = false;
        while(!cont)
        {
            cont = true;

            switch(this->currentWeapon)
            {
            case SWORD:
                cout << "Your current weapon is a sword that has a range of 1 and a damage rating of 5." << endl;
                cout << "In which direction do you wish to attack:" << endl;
                cout << "1) North, 2) South, 3) East, 4) West." << endl;
                int input;
                cin >> input;
                enemy *enemyToAttack;
                switch(input)
                {
                case 1:
                    this->attackDir = NORTH;
                    for(int i = 0; i < listOfEntities.size(); i++)
                    {
                        int xCor = listOfEntities[i]->xCoordinate;
                        int yCor = listOfEntities[i]->yCoordinate;
                        if((xCor == this->xCoordinate) && (xCor = this->yCoordinate+1))
                        {
                            enemyToAttack = listOfEntities[i];
                        }

                    }
                    break;
                case 2:
                    this->attackDir = SOUTH;
                    for(int i = 0; i < listOfEntities.size(); i++)
                    {
                        int xCor = listOfEntities[i]->xCoordinate;
                        int yCor = listOfEntities[i]->yCoordinate;
                        if((xCor == this->xCoordinate) && (xCor = this->yCoordinate-1))
                        {
                            enemyToAttack = listOfEntities[i];
                        }

                    }
                    break;
                case 3:
                    this->attackDir = EAST;
                    for(int i = 0; i < listOfEntities.size(); i++)
                    {
                        int xCor = listOfEntities[i]->xCoordinate;
                        int yCor = listOfEntities[i]->yCoordinate;
                        if((xCor == this->xCoordinate+1) && (xCor = this->yCoordinate))
                        {
                            enemyToAttack = listOfEntities[i];
                        }

                    }
                    break;
                case 4:
                    this->attackDir = WEST;
                    for(int i = 0; i < listOfEntities.size(); i++)
                    {
                        int xCor = listOfEntities[i]->xCoordinate;
                        int yCor = listOfEntities[i]->yCoordinate;
                        if((xCor == this->xCoordinate-1) && (xCor = this->yCoordinate))
                        {
                            enemyToAttack = listOfEntities[i];
                        }

                    }
                    break;
                default:
                    cont = false;
                    cout << "Invalid selection." << endl;
                    break;
                }
                if(enemyToAttack == NULL)
                {
                    player::takeInput();
                }
                enemyToAttack->health = health - 5;
                cout << "You attack the enemy for 5 damage!" << endl;
                cout << "They are now on " << enemyToAttack->health << "HP." << endl;
                break;
            case PISTOL:
                cout << "Your current weapon is a pistol that has a range of 4 and a damage rating of 3 with " << this->ammunition << " bullets remaining." << endl;
                cout << "In which direction do you wish to attack:" << endl;
                cout << "1) North, 2) South, 3) East, 4) West." << endl;
                cin >> input;
                switch(input)
                {
                case 1:
                    this->attackDir = NORTH;
                    for(int i = 0; i < 4; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate) && (xCor = this->yCoordinate+i))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                case 2:
                    this->attackDir = SOUTH;
                    for(int i = 0; i < 4; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate) && (xCor = this->yCoordinate-i))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                case 3:
                    this->attackDir = EAST;
                    for(int i = 0; i < 4; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate+i) && (xCor = this->yCoordinate))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                case 4:
                    this->attackDir = WEST;
                    for(int i = 0; i < 4; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate-i) && (xCor = this->yCoordinate))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                default:
                    cont = false;
                    cout << "Invalid selection." << endl;
                    break;
                }
                if(enemyToAttack == NULL)
                {
                    cout << "Your attack missed!" << endl;
                    break;
                }
                enemyToAttack->health = health - 3;
                cout << "You attack the enemy for 3 damage!" << endl;
                cout << "They are now on " << enemyToAttack->health << "HP." << endl;
                break;
            case RIFLE:
                cout << "Your current weapon is a rifle that has a range of 10 and a damage rating of 6 with " << this->ammunition << " bullets remaining." << endl;
                cout << "In which direction do you wish to attack:" << endl;
                cout << "1) North, 2) South, 3) East, 4) West." << endl;
                cin >> input;
                switch(input)
                {
                case 1:
                    this->attackDir = NORTH;
                    for(int i = 0; i < 10; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate) && (xCor = this->yCoordinate+1))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                case 2:
                    this->attackDir = SOUTH;
                    for(int i = 0; i < 10; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate) && (xCor = this->yCoordinate+1))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                case 3:
                    this->attackDir = EAST;
                    for(int i = 0; i < 10; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate+i) && (xCor = this->yCoordinate))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                // Confirm that there is nothing in the way of the move.se 4:
                    this->attackDir = WEST;
                    for(int i = 0; i < 10; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate-i) && (xCor = this->yCoordinate))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                default:
                    cont = false;
                    cout << "Invalid selection." << endl;
                    break;
                }
                if(enemyToAttack == NULL)
                {
                    cout << "Your attack missed!" << endl;
                    break;
                }
                enemyToAttack->health = health - 6;
                cout << "You attack the enemy for 6 damage!" << endl;
                cout << "They are now on " << enemyToAttack->health << "HP." << endl;
                break;
            case SHOTGUN:
                cout << "Your current weapon is a shotgun that has a range of 2 and a damage rating of 10 with " << this->ammunition << " cartridges remaining." << endl;
                cout << "In which direction do you wish to attack:" << endl;
                cout << "1) North, 2) South, 3) East, 4) West." << endl;
                cin >> input;
                switch(input)
                {
                case 1:
                    this->attackDir = NORTH;
                   for(int i = 0; i < 2; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate) && (xCor = this->yCoordinate+1))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                case 2:
                    this->attackDir = SOUTH;
                    for(int i = 0; i < 2; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate) && (xCor = this->yCoordinate-1))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                case 3:
                    this->attackDir = EAST;
                    for(int i = 0; i < 2; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinate+1) && (xCor = this->yCoordinate))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                case 4:
                    this->attackDir = WEST;
                    for(int i = 0; i < 2; i++)
                    {
                        for(int j = 0; j < listOfEntities.size(); j++)
                        {
                            int xCor = listOfEntities[j]->xCoordinate;
                            int yCor = listOfEntities[j]->yCoordinate;
                            if((xCor == this->xCoordinat-1) && (xCor = this->yCoordinate))
                            {
                                enemyToAttack = listOfEntities[j];
                            }

                        }
                        break;
                    }
                    cout << "Your attack missed!" << endl;
                    break;
                default:
                    cont = false;
                    cout << "Invalid selection." << endl;
                    break;
                }
                if(enemyToAttack == NULL)
                {
                    cout << "Your attack missed!" << endl;
                    break;
                }
                enemyToAttack->health = health - 10;
                cout << "You attack the enemy for 5 damage!" << endl;
                cout << "They are now on " << enemyToAttack->health << "HP." << endl;
                break;
            }
        }

    }
}

enemy.h：

#ifndef ENEMY_H
#define ENEMY_H

#include "entity.h"
#include <iostream>

class enemy : entity
{
    public:
        enemy();
        virtual ~enemy();
        void attackPlayer();
        void upgradeHealth();
        void upgradeWeapons();
        int health;
    protected:

    private:
};

#endif // ENEMY_H

enemy.cpp还没有代码。我使用GNU编译器与Code :: Blocks 谢谢！

Answer 1

您的tom <- data.frame(a = c(1,2,3), b = c("2017-01-09","2017-01-10","2017-09-11")) kate <- data.frame(a = c(4,5,6), b = c("2017-01-09","2017-01-10","2017-09-11")) testList <- list(tom,kate) f <- lapply(testList, function(x) { x[,2] <- as.Date(x[,2]) })类正在使用enemy的默认（私有）继承，因此它继承的所有entity字段（包括entity）都是私有且不可见在你的程序中的任何其他内容。在enemy.h中，您想要更改：

xCoordinate

为：

class enemy : entity
{
    // ...
}

这就是你（正确）为player.h中的class enemy : public entity { // ... }类设置它的方式。

这是C ++ FAQ中的一个页面，其中包含有关私有继承的更多详细信息：https://isocpp.org/wiki/faq/private-inheritance。

获取错误变量无法访问

1 个答案: