// overload7.cpp	By: Aiman Hanna -  ©1993-2006 Aiman Hanna
//
// This program illustrates the "this" class pointer. "this" is a pointer to the
// current object. That is, the address stored in the "this" pointer is the address
//  of the current object. "*this" indicates the contents of the "this" pointer. 
// Hence a statement such as "return *this;" would indicate return the invoking object
// (which is the current object). 
//
// This program overloads the "+=" operator to enable it to be used with 
// Vehicle objects. To clearly illustrate the idea, we assume that a statement 
// such as: v1 += v2; for two Vehicles v1, and v2 is to increment each data of 
// v1 by the similar data of v2. That is the number of doors of v1 will be 
// incremented by the number of doors of v2. Similarly, the maximum speed and 
// price of v1 will also be incremented by the maximum speed and price of v2.
// Sure, this is very unrealistic in real life!!
//
// Much more information concerning the "this" class pointer will be provided 
// when pointers are discussed.  
//
// Key Points: 		1) The "this" class pointer. 
//					


#include "overload7.h"



// Free function that overloads the iostream ">>" operator. 

istream& operator>> ( istream& is, Vehicle& vec )
{
 
	is >> vec.numdoors >> vec.maxspeed >> vec.price;
 
	return is; 
	    
}


// Free function that overloads the iostream "<<" operator. 

ostream& operator<< ( ostream& os, Vehicle& vec )
{
	os << " Here is the vehicle information: " << endl
	   << " the vehicle has " << vec.numdoors << " doors, maximum speed of " 
	   << vec.maxspeed << ", and its price is " << vec.price << endl << endl;
 
    return os;
 
}



Vehicle::Vehicle( int nd, double mxspd, double pr )
{
	numdoors = nd;
	maxspeed = mxspd;
	price = pr;

}




int Vehicle::GetNumDrs( void )
{
	return numdoors;
}



void Vehicle::SetNumDrs( int nd )
{
	numdoors = nd;
}




double Vehicle::GetmaxSpeed( void )
{
	return maxspeed; 
}




void Vehicle::SetMaxSpeed( double mxspd)
{
	maxspeed = mxspd;

}




double Vehicle::GetPrice( void )
{
	return price;

}




void Vehicle::SetPrice( double pr )
{
	price = pr;

}





Vehicle& Vehicle::operator+= ( const Vehicle& vec )
{
   // More information on "*" and "->" will be provided when pointers are discussed.
    this -> numdoors += vec.numdoors;		// same as numdoors += vec.numdoors;
    this -> maxspeed += vec.maxspeed;		// same as maxspeed += vec.maxspeed;
    this -> price += vec.price;			// same as price += vec.price;

    return *this;					// return the current object
}




int main()
{
	Vehicle v1(2, 120, 22000), v2(3, 100, 12000);
 

	cout << "\n Here is the information of v1: " << endl;
	cout << " ============================== " << endl;
	cout << v1;

	cout << "\n Here is the information of v2: " << endl;
	cout << " ============================== " << endl;
	cout << v2;


	v1 += v2; // Use the "+=" operator to increment data of v1 by data of v2.

	cout << "\n Here is the information of v1 after incrementing its price: " << endl;
	cout << " ============================================================== \n" << endl;
	cout << v1;

 

	Vehicle v3(3, 180, 1000), v4(2, 120, 2000), v5(3, 140, 30000);

	cout << "\n Here is the information of v3: " << endl;
	cout << " ============================== " << endl;
	cout << v3;

	cout << "\n Here is the information of v4: " << endl;
	cout << " ============================== " << endl;
	cout << v4;

	cout << "\n Here is the information of v5: " << endl;
	cout << " ============================== " << endl;
	cout << v5;

 // Now you can use the "+=" operator in a similar fashion to the original operator
 // provided by the language. That is the reason we have a "Vehicle&" as a return 
 // type from the function. 

	v3 = v4 += v5;


	cout << "\n Here is the information of v3 after being updated: " << endl;
	cout << " ==================================================== " << endl;
	cout << v3;

	cout << "\n Here is the information of v4 after being updated: " << endl;
	cout << " ==================================================== " << endl;
	cout << v4;

	return 0;
}




// The result of running the program 
/*
 

Here is the information of v1:
==============================
Here is the vehicle information:
the vehicle has 2 doors, maximum speed of 120, and its price is 22000


Here is the information of v2:
==============================
Here is the vehicle information:
the vehicle has 3 doors, maximum speed of 100, and its price is 12000


Here is the information of v1 after incrementing its price:
==============================================================

Here is the vehicle information:
the vehicle has 5 doors, maximum speed of 220, and its price is 34000


Here is the information of v3:
==============================
Here is the vehicle information:
the vehicle has 3 doors, maximum speed of 180, and its price is 1000


Here is the information of v4:
==============================
Here is the vehicle information:
the vehicle has 2 doors, maximum speed of 120, and its price is 2000


Here is the information of v5:
==============================
Here is the vehicle information:
the vehicle has 3 doors, maximum speed of 140, and its price is 30000


Here is the information of v3 after being updated:
====================================================
Here is the vehicle information:
the vehicle has 5 doors, maximum speed of 260, and its price is 32000


Here is the information of v4 after being updated:
====================================================
Here is the vehicle information:
the vehicle has 5 doors, maximum speed of 260, and its price is 32000

*/