Polymorphism/classes

[XodoX]

Hello, I got the following code:

#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std ;

// Function Prototypes

void pause(void);

/** defines an abstract class */
class Jukebox {
public:
   virtual void play() { cout << "Record unknown\n" ; }
} ;

/** defining subclasses */
class NewAge: public Jukebox {
public:
   void play() { cout << "NewAge is playing\n\n" ; }
} ;

class RandB: public Jukebox {
public:
   void play() { cout << "R&B is playing\n\n" ; }
} ;

class BlueGrass: public Jukebox {
public:
   void play() { cout << "Blue Grass is playing\n\n" ; }
} ;

/** An entry point for program execution */
int main() {
   Jukebox *pointer[3] = {new NewAge(), new RandB(), new BlueGrass()} ;
   
   // set seed for the random generator
   srand( (unsigned)time(NULL) ) ;

   // runs a test
   for (int i=0; i < 10; i++) {
      int index = rand() % 3 ;
      pointer[index]->play() ;  // polymorphic funcation call
   }



pause();
return 0;
}


I want to write my own set of classes with polymorphism support for a problem involving automobiles and different model of cars, such as, "Ford Mustang" and so on.
Do I just have to substitute "Jukebox", "New Age" etc.? I guess Toyota would be the main class and Yaris the subclass?

[firstPerson]

I would suggest the following :

1) create an abstract base class that has the similar properties for
all class

2) Derive a base class from the abstract, maybe a CarType class

3) Derive a Toyota, Honda, Lexus ... from CarType

[crazyboy]

Hello ,

you want polymorphism for car,

for that u can create a base class like name CAR
i.e.

class car{

}

you can define some abstart or virtual method in this base class
like color of car,price or model etc,which will be common for any class.

so if u create such virtual method in base class class,
all child class need to have this method ,
so some method which u think that, that should for all car can be define in base class.

you can inherit this class in other classes like ford ,toyota....

and ford and toyota wll be inherited in the cars like carolla and iCon and all..........

u can define some unique property of each car in that specific car class i.e. you can define some specific feature of iCon car in to iCon class and common feature of FORD company can be there in ford class and common for all car will be in CAR class,the parent class for all other classes

[XodoX]

I still don't quite get it. Jukebox would be "cartype'. New Age, RandB and Bluegrass would be the brands...? BMW, Ford etc.

[XodoX]

Now, that's what I did. It lists each type now multiple times... didn't do that before...

#include <iostream>
#include <cstdlib>
#include <ctime>

using namespace std ;

// Function Prototypes

void pause(void);


class Car {
public:
virtual void play() { cout << "Car unknown\n" ; }
} ;


class Toyota: public Car {
public:
void play() { cout << "Toyota Prius\n" ; }
} ;

class Ford: public Car {
public:
void play() { cout << "Ford Mustang\n" ; }
} ;

class Volkswagen: public Car {
public:
void play() { cout << "Volkswagen Jetta\n" ; }
} ;


int main() {
Car *pointer[3] = {new Toyota(), new Ford(), new Volkswagen()} ;

// set seed for the random generator
srand( (unsigned)time(NULL) ) ;

// runs a test
for (int i=0; i < 10; i++) {
int index = rand() % 3 ;
pointer[index]->play() ; 
}

system("pause");
return 0;
}

At least it's a lsit and a random output. Is that kinda it what you guys meant?

[crazyboy]

Then,
I think you r not so clear about concept of Polymophism.

if yes,
then you should be first clear about your concepts ,
for that you can refer books.