1、类的组合

点，线，三角形。

期望输入：

请输入点1的x的值：12.5

请输入点1的y的值：53.3

请输入点2的x的值：223.7

请输入点2的y的值：62.9

请输入点3的x的值：11.4

请输入点3的y的值：56.3

期望输出：

点1的坐标为：(12.5,53.3)

点2的坐标为：(223.7,62.9)

点3的坐标为：(11.4,56.3)

线1长度:211.418

线2长度:212.403

线3长度:3.19531

该三角形的周长为：427.016

该三角形的面积为：322.08

#include<iostream>
#include<math.h>
using namespace std;

class myPoint
{
public:
	myPoint();
    myPoint(double x,double y);
    double getX();
    double getY();
private:
    double mX,mY;
};
myPoint::myPoint(double x,double y):mX(x),mY(y){}
double myPoint::getX()
{
	return mX;
}
double myPoint::getY()
{
	return mY;
}
class  Line
{
public:
	Line(myPoint& p,myPoint& p0):m_p(p),m_p0(p0){}
	double GetDistance()
	{
		return sqrt(pow(m_p.getX()-m_p0.getX(),2)+pow(m_p.getY()-m_p0.getY(),2));
	}
private:
	myPoint m_p,m_p0;
};
class Triangle
{
public:
	Triangle(myPoint& p1,myPoint& p2,myPoint& p3,double a=0,double b=0,double c=0):m_p1(p1),m_p2(p2),m_p3(p3),m_a(a),m_b(b),m_c(c){}
	double getGirth()
	{
		m_a=sqrt(pow(m_p1.getX()-m_p2.getX(),2)+pow(m_p1.getY()-m_p2.getY(),2));
		m_b=sqrt(pow(m_p2.getX()-m_p3.getX(),2)+pow(m_p2.getY()-m_p3.getY(),2));
		m_c=sqrt(pow(m_p3.getX()-m_p1.getX(),2)+pow(m_p3.getY()-m_p1.getY(),2));
		return m_a+m_b+m_c;
	}
	double getArea()
	{
		return sqrt(getGirth()/2.0*(getGirth()/2.0-m_a)*(getGirth()/2.0-m_b)*(getGirth()/2.0-m_c));
	}
private:
	myPoint m_p1,m_p2,m_p3;
	double m_a,m_b,m_c;
};
int main()
{
	double x1,x2,x3,y1,y2,y3;
    cout<<"请输入点1的x的值：";
    cin>>x1;
    cout<<"请输入点1的y的值：";
    cin>>y1;
    cout<<"请输入点2的x的值：";
    cin>>x2;
    cout<<"请输入点2的y的值：";
    cin>>y2;
    cout<<"请输入点3的x的值：";
    cin>>x3;
    cout<<"请输入点3的y的值：";
    cin>>y3;
    cout<<"点1的坐标为：("<<x1<<","<<y1<<")"<<endl;
    cout<<"点2的坐标为：("<<x2<<","<<y2<<")"<<endl;
    cout<<"点3的坐标为：("<<x3<<","<<y3<<")"<<endl;
    myPoint p1(x1,y1),p2(x2,y2),p3(x3,y3);
    Line line1(p1,p2);
    Line line2(p2,p3);
    Line line3(p3,p1);
    cout<<"线1长度:"<<line1.GetDistance()<<endl;
    cout<<"线2长度:"<<line2.GetDistance()<<endl;
    cout<<"线3长度:"<<line3.GetDistance()<<endl;
    Triangle t(p1,p2,p3);
    cout<<"该三角形的周长为："<<t.getGirth()<<endl;
    cout<<"该三角形的面积为："<<t.getArea()<<endl;
    return 0;
}

2、虚基类与继承

以学校职工为基类，派生出教师类和管理人员类，又从教师类和管理人员类共同派生出教师管理人员类。

期望输出：

Zhao is a staff, 20 yeas old.

Zhang is a teacher, 30 yeas old, Lecturer.

Wang is a manager, 50 yeas old, Dean.

Li is a teacher manager, 40 yeas old, Peofessor, Department head.

#include  <iostream>  
using  namespace  std;
#include<string>
class  Staff  
{    
protected:
        int  number;
        string  name;
        int  age;
public:
        Staff(int  num,const  string  na,int  a)  
        {        
                number  =  num;
                name  =  na;
                age  =  a;
        }
        void  Display()
        {        
                cout<<name<<"  is  a  staff,  "<<age<<"  yeas  old."<<  endl;    
        }
};  

class  Teacher:virtual public Staff
{
protected:
        string  title;          //职称
public:
        Teacher(int  num,const  string  na,int  a,const  string  ttl);
        void  Display()
        {
                cout<<name<<"  is  a  teacher,  "<<age<<"  yeas  old,  "<<title<<".  "<<endl;
        }
};

Teacher::Teacher(int  num,  const  string  na,  int  a,const  string  ttl):Staff(num,na,a)
{
        title  =  ttl;
}


class  Management:virtual public Staff
{
protected:
        string  post;                          //职务
public:
        Management(int  num,const  string  na,  int  a,const  string  pt);
        void  Display()
        {
                cout<<name<<"  is  a  manager,  "<<age<<"  yeas  old,  "<<post<<".  "<<endl;
        }
};

Management::Management(int    num,const  string  na,  int  a,const  string  pt):Staff(num,na,a)
{
        post  =  pt;
}


class  TeacherManagement:public Teacher,public Management
{
public:
        TeacherManagement(int  num,const  string  na,  int  a,  const  string  ttl,const  string  pt);
        void  Display()
        {
                cout<<name<<"  is  a  teacher  manager,  "<<age<<"  yeas  old,  "  <<  title  <<",  "<<post<<".  "<<endl;
        }
};  

TeacherManagement::TeacherManagement(int  num,const  string  na,  int  a,  const  string  ttl,const  string  pt):
Staff(num,na,a),Teacher(num,na,a,ttl),Management(num,na,a,pt)

{
        number  =  num;
        age  =  a;
        name  =  na;
        title  =  ttl;
        post  =  pt;
}
int  main()
{
        Staff  s1(1,"Zhao",20);

        Teacher  t1(2,"Zhang",30,"Lecturer");

        Management  m1(3,"Wang",50,"Dean");

        TeacherManagement  tm1(4,"Li",40,"Peofessor","Department head");

        s1.Display();
        t1.Display();
        m1.Display();
        tm1.Display();
        return  0;
}