C++ object oriented programming, the polymorphism without the virtual function code sample

Compiler: Visual C++ Express Edition 2005

Compiled on Platform: Windows XP Pro SP2

Header file: Standard

Additional library: none/default

Additional project setting: Set project to be compiled as C++

Project -> your_project_name Properties -> Configuration Properties -> C/C++ -> Advanced -> Compiled As: Compiled as C++ Code (/TP)

Other info: none

To do: Displaying some data to demonstrate the C++ object oriented programming, the polymorphism without the virtual function in C++ programming

To show: The C++ object oriented programming, the polymorphism without the virtual function

#include<iostream>

usingnamespace std;

class vehicle

{

int wheels;

float weight;

public:

// first message(), no virtual modifier use here. Any derived (inherited) class function

// that have the same function/method signature cannot override this (base class) message() version

void message(void)

{

cout<<"Vehicle message(), from vehicle, the base class"<<endl;

}

};

class car : public vehicle

{

int passenger_load;

public:

//second message()

void message(void)

{

cout<<"Car message(), from car, the vehicle derived class"<<endl;

}

};

class truck : public vehicle

{

int passenger_load;

float payload;

public:

int passengers(void)

{

return passenger_load;

}

// no message()

};

class boat : public vehicle

{

int passenger_load;

public:

int passengers(void)

{

return passenger_load;

}

//third message()

void message(void)

{

cout<<"Boat message(), from boat, the vehicle derived class"<<endl;

}

};

int main()

{

cout<<"Without the virtual keyword for the base class function"<<endl;

cout<<"any derived (inherited) class function cannot override the base class function,"<<endl;

cout<<"all derived (inherited) class function with same signature as the base class"<<endl;

cout<<"will use the base class function version..."<<endl;

cout<<"---------------------------------------------------------------------------"<<endl;

vehicle *unicycle;

// allocate memory for vehicle class object

unicycle =new vehicle;

unicycle->message();

delete unicycle;

unicycle = NULL;

// will use the base class message(), cannot override

unicycle =new car;

unicycle->message();

delete unicycle;

unicycle = NULL;

// no message(), use the base class message()

unicycle =new truck;

unicycle->message();

delete unicycle;

unicycle = NULL;

// will use the base class message(), cannot override

unicycle =new boat;

unicycle->message();

delete unicycle;

unicycle = NULL;

// unicycle = sedan_car;

// unicycle->message();

return 0;

}