C++课本第四章例题

时钟类的完整例题

#include <iostream>
using namespace std;
class Clock{
    private :
        int hour,minute,second;
    public:
        void setTime(int hour=0,int minute=0,int second=0);
        void showTime();
};
void Clock::setTime(int newH,int newM,int newS)
{
    hour=newH;
    minute=newM;
    second=newS;
}
void Clock::showTime()
{
    cout<<hour<<"/"<<minute<<"/"<<second<<endl;
}
int main()
{
    Clock myclock;
    myclock.setTime();
    myclock.showTime();
    myclock.setTime(11,2,3);
    myclock.showTime();
}

 点和线的组合类例题

#include <iostream>
#include <cmath>
using namespace std;
class Point{
    public:
        Point(int xx=0,int yy=0){
            x=xx;
            y=yy;
        }
        Point(Point &p);
        int getx(){
            return x;
        }
        int gety(){
            return y;
        }
    private:
        int x;
        int y;
};
Point::Point(Point &p)
{
    x=p.x;
    y=p.y;
    cout<<"copy"<<endl;
}
class Line{
    public:
        Line(Point xp1,Point xp2);
        Line(Line &l);
        double getline(){
            return len;
        }
        private:
            double len;
            Point p1,p2;        
};
Line::Line(Point xp1,Point xp2):p1(xp1),p2(xp2){
    cout<<"line"<<endl;
    double x=static_cast<double> (p1.getx()-p2.getx());
    double y=static_cast<double> (p1.gety()-p2.gety());
    len=sqrt(x*x+y*y);
}
Line::Line(Line &l):p1(l.p1),p2(l.p2){
    cout<<"copy line"<<endl;
    len=l.len;
}
int main()
{
    Point myp1(1,1),myp2(4,5);
    Line line(myp1,myp2);
    Line line2(line);
    cout<<"the length of the line is:";
    cout<<line.getline()<<endl;
    cout<<"the length of the line2 is:";
    cout<<line2.getline()<<endl;
    return 0;
}