Decorator

C++ Code:

#include <iostream>

class Componet
{
public:
	virtual int CalCost(void) = 0;
};

class ComponetBase : public Componet
{
private:
	int _baseCost;

public:
	ComponetBase(int bc) : _baseCost(bc) {}
	virtual int CalCost(void) { return _baseCost; }
};

class Decorator : public Componet
{
private:
	int			_decCost;
	Componet* 	_preDecoratorPtr;
public:

	Decorator(Componet* prePtr, int decCost): \
	_decCost(decCost), _preDecoratorPtr(prePtr) {}

	virtual int CalCost(void) { return _decCost + _preDecoratorPtr->CalCost(); }
};

int main(int argc, char const *argv[])
{
	int coffeeBaseCost 	= 10;
	int sugarCost		= 8;
	int milkCost		= 6;

	ComponetBase coffee(coffeeBaseCost);
	std::cout << "Only Coffee Price = " << coffee.CalCost() << std::endl;

	Decorator coffeeWithSugar(&coffee, sugarCost);
	std::cout << "Coffee with Sugar Price = " << coffeeWithSugar.CalCost() << std::endl;

	Decorator coffeeWithMilk(&coffee, milkCost);
	std::cout << "Coffee with Milk Price = " << coffeeWithMilk.CalCost() << std::endl;

	Decorator coffeeWithMilkAndSugar(&coffeeWithMilk, sugarCost);
	std::cout << "Coffee with Milk and Sugar Price = " << \
	coffeeWithMilkAndSugar.CalCost() << std::endl;

	return 0;
}

OutPut:
Only Coffee Price = 10
Coffee with Sugar Price = 18
Coffee with Milk Price = 16
Coffee with Milk and Sugar Price = 24

Python Code:

class Componet(object):
	def CalCost(self):
		pass

class ComponetBase(Componet):
	def __init__(self, baseCost):
		self._baseCost = baseCost
	
	def CalCost(self):
		return self._baseCost
	
	def SetVal(self, val):
		self._baseCost = val
	
class Decorator( Componet ):
	def __init__(self, preComponetRef, baseCost):
		self._baseCost 			= baseCost
		self._preComponetRef 	= preComponetRef
		
	def CalCost(self):
		return self._baseCost + self._preComponetRef.CalCost()
	
	
if "__main__" == __name__:
	coffeePrice = 10
	sugarPrice	= 8
	milkPrice 	= 6
	
	coffee 			= ComponetBase(coffeePrice)
	print 'Only coffee = ', coffee.CalCost()
	
	coffeeWithSugar = Decorator(coffee, sugarPrice)
	print 'Coffee with sugar = ', coffeeWithSugar.CalCost()
	
	coffeeWithSugarAndMilk = Decorator(coffeeWithSugar, milkPrice)
	print 'Coffee with sugar and milk = ', coffeeWithSugarAndMilk.CalCost()