无法初始化具有已知大小且不会因多态性而改变的向量指针

Question

我正在制作具有继承性和多态性的蛇梯游戏。该板由可以是普通，蛇形或梯形的瓷砖制成。因此，我有一个具有可变类型Board（抽象类）的类Tile，该类型可以是Snake（子类）或Ladder（子类）。董事会可以像用户希望的一样大，因此，我正在使用矢量指针Tile。

我想用板子的大小给定的固定大小来初始化这样的向量，但是我看到一个错误消息“ function Board::getBoardSize() is not a type name”，但我发现互联网上的每个人甚至我的教授都像这样初始化向量。

[注：Board是在另一个类（MyGame）中构造的，特别是在称为start()的函数中，而在主体中，我只是创建了一个对象类型MyGame来调用start函数，因此一切都会发生。

Board.h：

#ifndef BOARD_H
#define BOARD_H
#include <vector>
#include "Tile.h"

class Board
{
    public:
        Board(int, int);
        ~Board();
        void setBoardSize(int);
        void setNumSnakes(int);
        void setNumLadders(int);
        int getBoardSize();
        int getNumSnakes();
        int getNumLadders();

    public:
        int boardSize;
        int numSnakes;
        int numLadders;
        std::vector<Tile*> place (getBoardSize());  -<------ I get the error here.
};
#endif

Board.cpp：

#include <stdlib.h>
#include <time.h>
#include <iostream>
#include "Board.h"
#include "Snake.h"
#include "Ladder.h"

Board::Board(int rwrd, int pnlty)
{
    //initialize random seed to randomize snakes and ladders.
    srand(time(NULL));

    int index = rand() % getBoardSize() + 1;

    // All tiles are set to 'N' when the array of Tiles is created.

    //Creates (numSnakes value) Snake objets inside the vector Tile pointer in random indexes.
    for(int i = 0; i < getNumSnakes(); i++)
    {
        /*
            Makes sure it only replaces tiles when:
            - with type = 'N'
            - there is no 'S' tiles before tile 4.
            - there is no 'S' (penlaty value) tiles before the end.
        */
        while (index < pnlty || index > (getBoardSize() - pnlty) || place[index]->getType() != 'N')
            index = rand() % boardSize + 1;

        place[index] = new Snake(pnlty);
    }

    index = rand() % getBoardSize() + 1;

    //Creates (numLadders value) Ladder objets inside the vector Tile pointer in random indexes.
    for(int i = 0; i < getNumLadders(); i++)
    {
        /*
            Makes sure it only replaces tiles when:
                - with type = 'N'.
                - there is no 'L' tiles before tile 4.
                - there is no 'L' (reward value) tiles before the end.
        */
        while (index < rwrd || index > (getBoardSize() - rwrd) || place[index]->getType() != 'N')
            index = rand() % boardSize + 1;

        place[index] = new Ladder(rwrd);
    }
}

Board::~Board()
{

}

void Board::setBoardSize(int SIZE)
{
    if(SIZE > 0)
        boardSize = SIZE;
    else
    {
        std::cout << "Board size has to be longer than zero" << std::endl;
        boardSize = 0;
    }
}

void Board::setNumSnakes(int numS)
{
    if(numS >= 0)
        numSnakes = numS;
    else
    {
        std::cout << "There can't be a negative number of snake tiles in the board." << std::endl;
        numSnakes = -1;
    }
}

void Board::setNumLadders(int numL)
{
    if(numL >= 0)
        numLadders = numL;
    {
        std::cout << "There can't be a negative number of ladder tiles in the board." << std::endl;
        numLadders = -1;
    }

}


int Board::getBoardSize()
{
    return boardSize;
}

int Board::getNumSnakes()
{
    return numSnakes;
}

int Board::getNumLadders()
{
    return numSnakes;
}

MyGame.h：

#ifndef MYGAME_H
#define MYGAME_H


class MyGame
{

    protected:
        int numPlayers;
        int maxTurns;

    public:
        MyGame();
        ~MyGame();
        void start();  <---------- Function where everything happens
        void setNumPlayers(int);
        void setMaxTurns(int);
        int setReward();
        int setPenalty();
        int getNumPlayers();
        int getMaxTurns();




};

#endif

MyGame.cpp：

#include <iostream>
#include "MyGame.h"
#include "Board.h"

MyGame::MyGame()
{

}

MyGame::~MyGame()
{

}

void MyGame::start()
{
    /*
    std::cout << "Number of player: ";
    std::cin >> numPlayers;
    std::cout << std::endl;

    std::cout << "Maximum number of turns: ";
    std::cin >> maxTurns;
    std::cout << std::endl;

    int r = setReward();   //I'm debugging so I'm just making sure the board is constructed right
    int p = setPenalty();
    */
    numPlayers = 2;
    maxTurns = 20;

    Board brd(3,3);

    for(int i = 0; i < brd.getBoardSize(); i++)
        std::cout << i + 1 << brd.place[i]->getType() << std::endl;


}

void MyGame::setNumPlayers(int numP)
{
    if(numP > 1)
        numPlayers = numP;
    else
    {
        std::cout << "The number of players isn't enough to start." << std::endl;
        numPlayers = 0;
    }

}

void MyGame::setMaxTurns(int max)
{
    if(max > 0)
        maxTurns = max;
    else
    {
        std::cout << "The Limit  of turns has to be higger than 0" << std::endl;
        maxTurns = 0;
    }
}

int MyGame::setReward()
{
    int rew;
    while(true)
    {
        std::cout << "Reward (Ladder's consequence): ";
        std::cin >> rew;

        if(rew > 0)
            return rew;
        else if(rew < 0)
            return (rew * -1);
        else
            std::cout << "The Rewrd value can't be zero." << std::endl << std::endl;
    }
}

int MyGame::setPenalty()
{
    int pen;
    while(true)
    {
        std::cout << "Penalty (Snake's consequence): ";
        std::cin >> pen;

        if(pen > 0)
            return (pen * -1);
        else if(pen < 0)
            return pen;
        else
            std::cout << "The penalty value can't be zero." << std::endl << std::endl;
    }


}

int MyGame::getNumPlayers()
{
    return numPlayers;
}

int MyGame::getMaxTurns()
{
    return maxTurns;
}

main.cpp：

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

using namespace std;

int main()
{
    MyGame snakes;

    snakes.start();
    cin.get();
}

Answer 1

所以似乎有两个错误，第一个是技术错误。编写要编写的代码的方法是在构造函数初始化列表中创建板，像这样]

Board::Board(int rwrd, int pnlty) : place (getBoardSize())
{
    ...
}
但是第二个问题似乎更严重。在您的代码中没有看到任何表明您知道创建Board对象时的木板尺寸的信息。在您发布的代码中，仅在调用setBoardSize方法后才知道板子的大小，据我所知这从未发生。

您可能应该使电路板的尺寸成为构造函数的参数。