Xây dựng lớp cơ sơ trừu tượng engine

[tran_thom]

#include<iostream>
#include<conio.h>
#include<string.h>
using namespace std;
//dinh nghia lop Car
class car
{
    private :
        int speed;          //toc do
        char *mark;         //nhan hieu
        float price;        //gia ca
    public:
        void setmark(char *);
        char *getmark();
        void setspeed(int);
        int  getspeed();
        void setprice(float);
        float getprice();
        car(int speedin=0,char *markin="" ,float pricein=0);
        void show();
        ~car();
};
car::car(int speedin, char *markin, float pricein)
{
    setspeed(speedin);
    mark = new char [strlen(markin)+1]; //cap phat dong cho nhan hieu xe
    strcpy(mark,markin);
    setprice(pricein);
}
void car::setmark(char *markin)
{
    mark = new char [strlen(markin)+1];
    strcpy(mark,markin);
}
char *car::getmark()
{
    return mark;
}
void car::setspeed(int speedin)
{
    speed=speedin;
}
int car::getspeed()
{
    return speed;
}
void car::setprice(float pricein)
{
    price=pricein;
}
float car::getprice()
{
    return price;
}
void car::show()
{
    cout << "day la hang xe " << mark << "co toc do "
         << speed <<" km/h va voi gia " << price << "$\n";
}
car::~car()
{
    delete mark;
}
//dinh nghia lop bus ke thua tu lop car, them kieu label
class bus:public car
{
    private:
        int label;              //so hieu tuyen xe bus
    public:
        void setlabel(int);
        int getlabel();
        bus(int speedin=0, char *markin="", float pricein=0, int labelin=0);//khoi tao tham so day du
        void show();
};
bus::bus(int speedin, char *markin, float pricein, int labelin):car(speedin, markin, pricein)
{
    setlabel(labelin);
}

void bus::setlabel(int labelin)
{
    label = labelin;
}
int bus::getlabel()
{
    return label;
}
void bus::show()//dinh nghia chong phuong thuc show() cua lop co so
{
    car::show();
    cout << "tuyen so " << label<< endl;
}
/*
int main()
{
    bus mybus;
    int speedin, labelin;
    float pricein;
    char markin[20];

    cout<<"nhap nhan hieu xe";
    cin>>markin;
    cout<<"nhap toc do xe";
    cin>>speedin;
    cout<<"nhap gia tri cua xe";
    cin>>pricein;
    cout<<"nhap hieu so xe";
    cin>>labelin;
    mybus.setmark(markin);
    mybus.setspeed(speedin);
    mybus.setprice(pricein);
    mybus.setlabel(labelin);
    mybus.show();
    return 0;
}
*/
int main()
{
    car c(120,"Honda civic",20000);
    c.show();//phuong thuc cua lop car

    bus b(100,"\Huyndai",15000,26);
    b.getlabel();
    b.show();//phuong thuc cua lop bus

    cout<<"\nchuyen doi kieu giua lop dan xuat va lop co so"<<endl;
    c=b;
    c.show();
    return 0;
}