#include <iostream>
#include <string>

using namespace std;

class Person
{
public:
	void Print()
	{
		cout << "name:" << _name << endl;
		cout << "age:" << _age << endl;
	}
protected:
	string _name = "peter"; // 姓名
	int _age = 18;
};
class Student : public Person
{
protected:
	int _stuid;
};
int main()
{
	Person p;
	Student s;
	p.Print();
	s.Print();
	return 0;
}

#include <iostream>
#include <string>
using namespace std;

class Person
{
public:
	    // 缺省
		string _name = "陳志浩"; // 姓名
		string _sex = "男"; // 性別
		int _age = 25; // 年齡
};
class Student : public Person
{
public:
	int _No = 2019124084; // 學(xué)號
};

void Test()
{
	Person pobj;
	Student sobj;
	// 修改子類的成員變量方便演示
	sobj._name = "chenzhiiao";
	sobj._age = 23;
}
int main()
{
	Test();
	return 0;
}

#include <iostream>
using namespace std;

class A {
public:
	void fun()
	{
		cout << "func()" << endl;
	}
};
class B : public A {
public:
	void fun(int i)
	{
		cout << "func(int i)->" << i << endl;
	}
};
void Test()
{
	// B中的fun和A中的fun不是構(gòu)成重載，因為不是在同一作用域
	// B中的fun和A中的fun構(gòu)成隱藏，成員函數(shù)滿足函數(shù)名相同就構(gòu)成隱藏。
	B b;
	b.fun(10);
	b.A::fun();//可以使用 基類::基類成員 顯示訪問
};
int main()
{
	Test();
	return 0;
}

#include <iostream>
#include <string>
#include <ostream>
using namespace std;
class Person
{
public:
	friend ostream& operator<<(ostream& out, const Person& p);
	Person(const char* name = "peter")
		: _name(name)
	{
		cout << "Person()" << endl;
	}

	Person(const Person& p)
		: _name(p._name)
	{
		cout << "Person(const Person& p)" << endl;
	}

	Person& operator=(const Person& p)
	{
		cout << "Person& operator=(const Person& p)" << endl;
		if (this != &p)
			_name = p._name;

		return *this;
	}

	~Person()
	{
		cout << "~Person()" << endl;
	}
protected:
	string _name; // 姓名
};
ostream& operator<<(ostream& out, const Person& p)
{
	out << "name : " << p._name << endl;
	return out;
}
class Student : public Person{
public:
	friend ostream& operator<<(ostream& out, const Student& s);
	Student(const char* name = "chenzhiao", int no = 2019)
		:Person(name)
		,_no(no)
	{
		cout << "Student()" << endl;
	}
	
	~Student()
	{
		cout << "~Student()" << endl;
	}

protected:
	int _no;
};
ostream& operator<<(ostream& out, const Student& s)
{
	out << "name : " << s._name << ",no : " << s._no << endl;
	return out;
}

void Test()
{
	Student s1;	
	cout << s1;
};
int main()
{
	Test();
	return 0;
}

Student(const Student& s)
		: Person(s), _no(s._no)
	{
		cout << "Student(const Student& s)" << endl;
	}

Student& operator=(const Student& s)
	{
		if (this != &s)
		{
			Person::operator=(s); 
			//這里必須要用類名指定，否則子類的operator=會把父類的
			//的operator=隱藏掉，導(dǎo)致無限遞歸調(diào)用子類的operator=導(dǎo)致棧溢出
			_no = s._no;
		}
		return *this;
	}

~Student()
	{
		cout << "~Student()" << endl;
		Person::~Person(); 
		//C++的編譯器保證了這個代碼默認會執(zhí)行，但是必須要放在最后一行才符合規(guī)則
		//不能讓程序員去手動指定Person::~Person();必須要放在最后一行
		//萬一程序員不小心放在了第一行，會導(dǎo)致一些不可預(yù)料的錯誤，所以不要顯示調(diào)用
		//這和上面3個默認成員的規(guī)則不一樣，需要多注意
	}

#include <iostream>
#include <string>
using namespace std;

class Person
{
public:
	Person() { ++_count; }
protected:
	string _name; // 姓名
public:
	static int _count; // 統(tǒng)計人的個數(shù)。
};
int Person::_count = 0;
class Student : public Person
{
protected:
	int _stuNum; // 學(xué)號
};
class Graduate : public Student
{
protected:
	string _seminarCourse; // 研究科目
};
void TestPerson()
{
	Student s1;
	Student s2;
	Student s3;
	Graduate s4;
	Person s5;
	cout << " 人數(shù) :" << Person::_count << endl;
	Student::_count = 0;
	cout << " 人數(shù) :" << Person::_count << endl;
}
int main()
{
	TestPerson();
	return 0;
}

#include <iostream>
#include <string>
using namespace std;

class Person{
public:
	string _name;
};
class Student : public Person{
protected:
	int _stuId;
};
class Teacher : public Person{
protected:
	int _teaId;
};
class Assistant : public Student, public Teacher{
protected:
	string _majorCourse;
};
void Test()
{

	Assistant a;
	//a._name = "chenzhiao"; 這樣會有二義性無法明確知道訪問的是哪一個

	// 需要顯式指定訪問哪個父類的成員可以解決二義性的問題，但是數(shù)據(jù)冗余的問題還是無法解決

	a.Student::_name = "xxx";
	a.Teacher::_name = "yyy";
	
}
int main()
{
	Test();
	return 0;
}

#include <iostream>
#include <string>
using namespace std;

class Person{
public:
	string _name;
};
class Student : virtual public Person{
protected:
	int _stuId;
};
class Teacher : virtual public Person{
protected:
	int _teaId;
};
class Assistant : public Student, public Teacher{
protected:
	string _majorCourse;
};
void Test()
{

	Assistant a;
	a._name = "chenzhiao";
	
}
int main()
{
	Test();
	return 0;
}
// 在菱形繼承的“肩膀處”添加完 virtual 關(guān)鍵字，完成虛擬繼承，可以解決數(shù)據(jù)的二義性和冗余問題。我們來看一下監(jiān)視窗口

#include <iostream>
#include <string>
using namespace std;

class A {
public:
	int _a;
};
// class B : public A
class B : public A {
public:
	int _b;
};
// class C : public A
class C : public A {
public:
	int _c;
};
class D : public B, public C {
public:
	int _d;
};

void Test()
{
	D d;
	cout << sizeof(d) << "字節(jié)" << endl;
	d.B::_a = 1;
	d.C::_a = 2;
	d._b = 3;
	d._c = 4;
	d._d = 5;
	
}
int main()
{
	Test();
	return 0;
}