Error
E/C++/v1/算法：642：/Applications/Xcode.app/Content/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/utility：321：9： error：
字段类型"空间"是一个抽象类 _T2秒; ^
/Applications/Xcode.app/Content/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/map：624：16： 注意：
问题
我如何定义一个类型为Space的抽象类std::vector，然后用派生类的实例填充这个向量Empty、Snake、Ladder。
上下文
我知道C++中的抽象类不能实例化。相反，我在这个网站和其他网站上的几篇文章中读到，如果该类型被定义为星形*指针或任何<memory>托管指针数据类型(如std::unqiue_ptr<T>)，则可以创建抽象类型的集合。我尝试在我的情况下使用shared_ptr<Space>，但仍然无法正确定义集合。我使用g++ -std=c++17 main.cpp && ./a.out编译了我的代码。
法典
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <map>
#include <memory>
#include <typeinfo>
#include <queue>
#include <string>
#include <vector>
class Player
{
private:
int m_current_space = 1;
public:
Player() {}
void role_dice() {
m_current_space += floor( (rand()%10 + 1) / 3 );
}
int const get_current_space() {
return m_current_space;
}
void set_current_space(int current_space) {
m_current_space = current_space;
}
};
class Space
{
protected:
int m_id;
std::vector<Space> m_paths;
public:
Space() {} // requied to use [] operator in map
Space(int id) : m_id(id) {}
void add_path(Space& s) {
m_paths.push_back(s);
}
int get_id() {
return m_id;
}
virtual std::string class_type() = 0;
};
class Empty : public Space
{
public:
Empty(int id) : Space(id) {}
std::string class_type() {
return "Empty";
}
};
class Ladder : public Space
{
public:
Ladder(int id) : Space(id) {}
virtual void event(Player& p) {
p.set_current_space(1);
}
std::string class_type() {
return "Ladder";
}
};
class Snake : public Space
{
public:
Snake(int id) : Space(id) {}
virtual void event(Player& p) {
p.set_current_space(4);
}
std::string class_type() {
return "Snake";
}
};
class Board
{
private:
std::map<int, Space> m_board;
public:
void add_space(Space& s) {
m_board[s.get_id()] = s;
}
void draw_board() {
int i = 1;
for(auto const& [space_key, space] : m_board) {
if(i%3 == 0) {
std::cout << "○n";
}
else if(typeid(space) == typeid(Snake)) {
std::cout << "○-";
}
else {
std::cout << "○ ";
}
++i;
}
}
void update_player_on_board(int position) {
int i = 1;
for(auto const& [space_key, space] : m_board) {
if(i%3 == 0) {
if (space_key == position) {
std::cout << "●n";
}
else {
std::cout << "○n";
}
}
else if(typeid(space) == typeid(Snake)) {
std::cout << "○-";
}
else {
if (space_key == position) {
std::cout << "● ";
}
else {
std::cout << "○ ";
}
}
++i;
}
}
const std::map<int, Space> get_board() {
return m_board;
}
friend std::ostream &operator<<(std::ostream& os, const Board& b) {
return os;
}
};
class GameStateManager
{
private:
std::string m_state = "game over";
bool m_playing = false;
public:
std::string const get_state() {
return m_state;
}
void set_state(std::string state) {
m_state = state;
}
};
int main()
{
std::cout << "Welcome to Bowser's 9 board gamen";
std::cout << "Start? y(yes) n(no)n";
GameStateManager game_manager;
game_manager.set_state("playing");
auto space1 = std::make_shared<Space>(1);
auto space2 = std::make_shared<Space>(2);
auto space3 = std::make_shared<Space>(3);
auto space4 = std::make_shared<Space>(4);
auto space5 = std::make_shared<Space>(5);
auto space6 = std::make_shared<Space>(6);
auto space7 = std::make_shared<Space>(7);
auto space8 = std::make_shared<Space>(8);
auto space9 = std::make_shared<Space>(9);
std::vector<std::shared_ptr<Space>> v {
space1, space2, space3,
space4, space5, space6,
space7, space8, space9
};
Board bowsers_bigbad_laddersnake;
for(int i = 0; i < 10; ++i) {
bowsers_bigbad_laddersnake.add_space(*(v[i]));
}
bowsers_bigbad_laddersnake.draw_board();
Player mario;
int turn = 0;
while(game_manager.get_state() == "playing") {
std::cin.get();
std::cout << "-- Turn " << ++turn << " --" << 'n';
mario.role_dice();
bowsers_bigbad_laddersnake.update_player_on_board(mario.get_current_space());
if (mario.get_current_space() >= 9) {
game_manager.set_state("game over");
}
}
std::cout << "Thanks a so much for to playing!nPress any key to continue . . .n";
std::cin.get();
return 0;
}
您似乎已经删除了很多代码以在此处详细介绍。 有一个Space指针(智能或原始)。实例化所需的特定空间，用类型Space的指针指向它。示例std::shared_ptr<Space> pointerToSpace = std::make_shared<Snake> ("I'm a snake");现在，在不损失通用性的情况下，您只需使用指向空格pointerToSpace->class_type()的指针即可打印内容(具体类型)。是的，您可以在容器中收集shared_ptr。