c++ - 无法在构造函数中访问类的继承成员

Question

我是 C++ 的新手。我有简单的单元类和继承单元类的英雄类。 Hero 类有 2 个附加参数，但构造函数无法访问父类的参数。 这是 unit.hpp:

#ifndef UNIT_HPP
#define UNIT_HPP

#include <string>

using namespace std;

class Unit
{
public:
    unsigned short  max_health  = 100;
    string          name        = "Dummy";
    short           health      = 100;
    short           damage      = 10;
    bool            isDead      = 0;

    Unit();
    Unit(string, unsigned short, unsigned short);
};

#endif //UNIT_HPP

这里是 unit.cpp:

#include <string>
#include <iostream>

#include "unit.hpp"

using namespace std;

Unit::Unit()
{
    cout << "Dummy was created!" << endl;
};

Unit::Unit(string N, unsigned short HP, unsigned short AT):
    max_health(HP),
    name(N),
    health(HP),
    damage(AT)
{
    cout << N << " was created!" << endl;
};

这里是 hero.hpp:

#ifndef HERO_HPP
#define HERO_HPP

#include <string>

#include "unit.hpp"

class Hero : public Unit
{
public:
    unsigned short  max_mana    = 100;
    string          name        = "The Brave Warrior";
    short           mana        = 100;

    Hero (string, unsigned short, unsigned short, unsigned short);

};

#endif //HERO_HPP

最后，这是 hero.cpp:

#include <string>

#include "hero.hpp"

using namespace std;

Hero::Hero(string N, unsigned short HP, unsigned short MP, unsigned short AT):
    max_health(HP),
    max_mana(MP),
    name(N),
    health(HP),
    mana(MP),
    damage(AT)
{
    cout << "The Legendary Hero, " << N << ", was born!" << endl;
}

这是控制台输出:

src/hero.cpp: In constructor ‘Hero::Hero(std::__cxx11::string, short unsigned int, short unsigned int, short unsigned int)’:
src/hero.cpp:10:5: error: class ‘Hero’ does not have any field named ‘max_health’
     max_health(HP),
     ^
src/hero.cpp:13:5: error: class ‘Hero’ does not have any field named ‘health’
     health(HP),
     ^
src/hero.cpp:15:5: error: class ‘Hero’ does not have any field named ‘damage’
     damage(AT)
     ^

问题出在哪里？抱歉英语不好。我希望我问的问题对，对我来说有这么多新术语。先感谢您。

Answer 1

您的基类通常应负责通过构造函数 方法初始化其变量。

这个:

unsigned short  max_health  = 100;
string          name        = "Dummy";
short           health      = 100;
short           damage      = 10;
bool            isDead      = 0;

看起来不符合犹太洁食标准。这些成员应该在构造函数中初始化:

Unit::Unit()
: max_health(100),
name("Dummy"),
health(100),
damage(10),
isDead(false)
{ ; }

此外，对于 bool 变量，您应该使用 true 或 false，而不是数字。

编辑 1:成员名称重复
您的子类应避免使用与基类相同的变量名。

英雄中的那一行:

  string name;

遮蔽或隐藏基类成员:

  string name;

如果您更愿意遵守此约定，您应该使用作用域解析运算符 :: 来告诉编译器您指的是哪个成员:

Hero::name = "Hercules"; // Assign member in Hero class
Unit::name = "Person";   // Assign to member in Unit class.