一、运算符重载

 实例：（赋值运算符、自增自减运算符、插入提取运算符）

#include <iostream>using namespace std;class Person
{friend Person & operator+=(Person &L,const Person &R);friend Person & operator++(Person &O);friend const Person operator++(Person &O,int);friend ostream & operator<<(ostream & cout,const Person &p);friend istream & operator>>(istream &cin,Person &p);int a;int b;
public://无参构造函数Person() {}//有参构造函数Person(int a,int b):a(a),b(b){}//成员函数实现+=运算符重载
//    Person & operator+=(const Person &R)
//    {
//        a += R.a;
//        b += R.b;
//        return *this;
//    }//成员函数实现前++运算符重载
//    Person & operator++()
//    {
//        ++a;
//        ++b;
//        return *this;
//    }//成员函数实现后++运算符重载
//    const Person operator++(int)
//    {
//        Person temp;
//        temp.a = a++;
//        temp.b = b++;
//        return temp;
//    }void show(){cout << "a = " << a << endl;cout << "b = " << b << endl;}
};//全局函数实现+=运算符重载
Person & operator+=(Person &L,const Person &R)
{L.a += R.a;L.b += R.b;return L;
}//全局函数实现前++运算符重载
Person & operator++(Person &O)
{++O.a;++O.b;return O;
}
//全局函数实现后++运算符重载
const Person operator++(Person &O,int)
{Person temp;temp.a = O.a++;temp.b = O.b++;return temp;
}//全局函数实现插入
ostream & operator<<(ostream &cout,const Person &p)
{cout << p.a << endl;cout << p.b << endl;return  cout;
}
//全局函数实现提取
istream & operator>>(istream &cin,Person &p)
{cin >> p.a;cin >> p.b;return cin;
}
int main()
{Person p1(10,10);Person p2(20,20);cout << "--------- 实现+= ----------" << endl;//+=p1 += p2;p1.show();cout << "-------- 实现 前++ ---------" << endl;//前++Person p3(10,10);p1 = ++p3;p3.show();p1.show();cout << "-------- 实现 后++ ----------" << endl;//后++Person p4(10,10);p4 = p2++;p2.show();p4.show();cout << "-------- 实现cout ----------" << endl;cout << p1;cout << "-------- 实现cin ----------" << endl;cin >> p2;cout << p2;return 0;
}

二、静态成员

银行账户实例 

#include <iostream>using namespace std;//封装银行账户 类
class BankAccount
{
private:double balance; //余额static double interest_rate; //利率  静态数据成员 属于类的public://无参构造BankAccount() {}//有参构造函数BankAccount(double b):balance(b){}//静态成员函数 获取当前的利率static double getInterestRate(){return interest_rate;}//静态成员函数，设置当前利率static void setInterestRate(double rate){interest_rate = rate;}//静态成员函数 获取连本带利的余额static double getLastMoney(BankAccount &account){return account.balance*(1+interest_rate);}
};double BankAccount::interest_rate = 0.05;  //在类外初始化 静态数据成员int main()
{cout << "当前利率：" << BankAccount::getInterestRate() << endl;BankAccount::setInterestRate(0.03);cout << "当前利率：" << BankAccount::getInterestRate() << endl;BankAccount account1(1000.0);BankAccount account2(2000.0);cout << "第一个人连本带利的余额：" << BankAccount::getLastMoney(account1) << endl;return 0;
}

三、类的继承

实例

#include <iostream>using namespace std;class Person //父类
{
private:string name;int age;
public://无参构造函数Person(){cout << "父类的无参构造函数" << endl;}//有参构造函数Person(string name, int age):name(name),age(age){cout << "父类的有参构造函数" << endl;}//拷贝构造函数Person(Person const &other):name(other.name),age(other.age){cout << "父类的拷贝构造函数" << endl;}//拷贝赋值函数Person & operator=(const Person &p){name = p.name;age = p.age;cout << "父类的拷贝赋值函数" << endl;return *this;}void show(){cout << "父类的show函数" << endl;}~Person(){cout << "父类的析构函数" << endl;}
};class Stu:public Person // 子类/派生类
{
private:int id;int math;
public://无参构造函数Stu(){cout << "子类的无参构造函数" << endl;}//有参构造函数Stu(string name, int age, int id, int math):Person(name,age),id(id),math(math){cout << "子类的有参构造函数" << endl;}//子类的拷贝构造函数Stu(Stu const &p):id(p.id),math(p.math),Person(p){cout << "子类的拷贝构造函数" << endl;}//子类的拷贝赋值函数Stu & operator=(const Stu &p){Person::operator=(p);id = p.id;math = p.math;cout << "子类的拷贝构造函数" << endl;return *this;}void show(){cout << "子类的show函数" << endl;}~Stu(){cout << "子类的析构函数" << endl;}
};
int main()
{
//    cout << "----------------------无参构造函数-------" << endl;
//    Stu p;//    cout << "----------------------有参构造函数-------" << endl;
//    Stu p1("张三",8,1,99);//    cout << "----------------------拷贝构造函数-------" << endl;
//    Stu p2=p1;//    cout << "----------------------show函数-------" << endl;
//    p2.show();
//    p2.Person::show();Stu p1("张三",8,1,99);cout << "----------------------拷贝赋值函数-------" << endl;Stu p2;p2 = p1;return 0;
}

四、多继承

 实例

#include <iostream>using namespace std;
class Sofa
{
private:string sitting;
public://无参构造函数Sofa(){cout<< "Sofa的无参构造函数" << endl;}//有参构造函数Sofa(string sitting):sitting(sitting){cout<< "Sofa的有参构造函数" << endl;}void show(){cout << sitting << endl;}
};
class Bed
{
private:string sleep;
public://无参构造函数Bed(){cout<< "Sofa的无参构造函数" << endl;}//有参构造函数Bed(string sleep):sleep(sleep){cout<< "Sofa的有参构造函数" << endl;}void show(){cout << sleep << endl;}
};class Sofa_Bed:public Sofa,public Bed
{
private:int w;
public://无参构造函数Sofa_Bed(){cout<< "沙发床的无参构造函数" << endl;}//有参构造函数Sofa_Bed(string sit,string sleep,int w):Sofa(sit),Bed(sleep),w(w){cout<< "沙发床的有参构造函数" << endl;}
};
int main()
{//Sofa_Bed s;Sofa_Bed s1("可坐","可睡",5);s1.Sofa::show();s1.Bed::show();return 0;
}