c++ - 未在范围内声明的类对象

Question

我目前遇到一个问题，我似乎无法理解它为什么会发生。 在我的 (Unsplit) 程序中，我创建了一个类，它定义了一个实体对象，并且能够很好地处理它的创建和变量(正如我在添加

之前测试过的那样)

std::string getName(Entity)const;
std::string getType(Entity)const;
int getDamage(Entity)const;
int getHealth(Entity)const;

但是当我这样做时...即使它们已经在类里面公开声明并且我完全能够调用 Initialize();攻击();和 PrintStats()；很好，它没有看到其他四个，因此无法调用。

#include <iostream>
#include <string>
#include <math.h>
#include <stdlib.h>     /* srand, rand */
#include <time.h>       /* time */
using namespace std;

class Entity
{
public:
    Entity() { // default constructor

        name = "Human";
        type = "Normal";
        damage = 1;
        health = 100;

    }
    void printStats();
    void Initialize(string, string, int, int); //transformer or setting function
    void Attack(Entity&); //observer or getter function
    std::string getName(Entity)const;
    std::string getType(Entity)const;
    int getDamage(Entity)const;
    int getHealth(Entity)const;

private://data members and special function prototypes
    std::string name;
    std::string type;
    int damage;
    int health;

};

void summonEnemy(Entity&);

int main () {

    /* initialize random seed: */
    srand (time(NULL));

    Entity  Player;//declaring new class objects
    Entity  Enemy;//declaring new class objects
    Player.Initialize("Player", "Normal", 10, 90);
    summonEnemy(Enemy);

    return 0;

}

void summonEnemy(Entity &target) {

    target.Initialize("Enemy", "Normal", floor(rand() % 20 + 1), floor(rand() % 100));
   cout << "An " << getType(target) << " type " << getName(target) << " has appeared with " <<
        getHealth(target) << "HP and can do " << getDamage(target) << " damage.";

}

错误信息:

error:'getType' Was not defined in this scope.
error:'getName' Was not defined in this scope.
error:'getHealth' Was not defined in this scope.
error:'getDamage' Was not defined in this scope.

切断一些代码以缩小范围，以便只显示可能导致问题的原因...但老实说，它可能是我没有看到的简单问题。任何帮助表示赞赏。

Answer 1

您没有正确调用它们。它们是 Entity 类的成员，而不是独立的函数。从它们中删除 Entity 参数，因为它们已经有一个隐式的 Entity *this 参数，然后像这样调用它们:

class Entity
{
public:
    Entity(); // default constructor
    ...
    std::string getName() const;
    std::string getType() const;
    int getDamage() const;
    int getHealth() const;
    ...
};

Entity::Entity()
{
    Initialize("Human", "Normal", 1, 100);
}

std::string Entity::getName() const
{
    return name;
}

std::string Entity::getType() const
{
    return type;
}

int getDamage() const
{
    return damage;
}

int getHealth() const
{
    return health;    
}

void summonEnemy(Entity &target)
{
    target.Initialize("Enemy", "Normal", floor(rand() % 20 + 1), floor(rand() % 100));
    cout << "An " << target.getType() << " type " << target.getName() << " has appeared with " <<
        target.getHealth() << "HP and can do " << target.getDamage() << " damage.";
}