我想使用5个特定的类来设计结构:Person,Driver,Employee,Child和Parent。
-每个驾驶员都是一个人。
-每个员工都是驾驶员和一个人。
-每个孩子都是一个人。
-每个父母都是一个人,司机,雇员,可以有一个或多个孩子。
这就是我的想法:
class Parent {
public:
class Employee {
public:
class Driver {
public:
class Person {
string name;
int age;
public:
string GetName() { return name; }
void SetName(string name) { this->name = name; }
int GetAge() { return age; }
void SetAge(int age) { this->age = age; }
};
private:
Person person;
string carName;
public:
Person GetPerson() { return person;}
void SetPerson(Person person) { this->person = person;}
string GetCarName() { return carName; }
void SetCarName(string carName) { this->carName = carName;}
};
private:
Driver driver;
public:
Driver GetDriver() { return driver; }
void SetDriver(Driver driver) { this->driver = driver; }
};
class Child {
public:
class Person:public Employee::Driver::Person {
};
private:
Person person;
string nameOfSchool;
public:
Person GetPerson() { return person; }
void SetPerson(Person person) { this->person = person;}
string GetNameOfSchool(){ return nameOfSchool;}
void SetNameOfSchool(string nameOfSchool) { this->nameOfSchool = nameOfSchool;}
};
private:
Employee employee;
Child child;
public:
Employee GetEmployee() { return employee; }
void SetEmployee(Employee employee) { this->employee = employee;}
Child GetChild() { return child;}
void SetChild(Child child) { this->child = child;}
};
但是当我尝试类似的东西时:
Parent random_parent;
random_parent.GetEmployee().GetDriver().GetPerson().SetName("Joseph");
random_parent.GetEmployee().GetDriver().GetPerson().SetAge(80);
cout << random_parent.GetEmployee().GetDriver().GetPerson().GetName() << endl << random_parent.GetEmployee().GetDriver().GetPerson().GetAge();
我只得到这个垃圾值:
-858993460
如何使Parent
的任何实例正常工作,并能够从内部类name
访问和初始化age
和Person
?
之所以这样,是因为您的getter方法返回的是复制对象,而不是对内部字段的引用,这与Java或C#不同。检查文档C ++copy constructor/ move constructor
所以您SetName("Joseph");
将在临时堆栈对象中设置一个值。使用C ++,您可以使用许多简单的POD结构而不是类,而无需任何getter / setter方法,即
struct Person {
...
std::string name;
uint8_t age;
}
struct Driver {
...
Person person;
}
struct Employee {
...
Driver driver;
}
struct Parent {
...
Employee employee;
}
....
random_parent.employee.driver.person.name = "Joseph";
random_parent.employee.driver.person.age = 80;