Les modèles de conception C: motif de l'usine

       motif usine (modèle d'usine) est l'un des modèles de conception les plus couramment utilisés, sont des motifs creational, il offre la meilleure façon de créer des objets. Mode usine, lorsque nous créons un objet, pas exposé à créer une logique, et en appelant une interface unifiée pour pointer vers l'objet nouvellement créé.

Quand utiliser: Nous prévoyons de créer des objets différents dans des conditions différentes.

 Exemple de code:

// Shape.h
#pragma once


class Shape
{
public:
	Shape();
	~Shape();
	virtual void draw() = 0;
};

// Shape.cpp
#include "Shape.h"

Shape::Shape()
{
}


Shape::~Shape()
{
}

// Circle.h
#pragma once
#include "Shape.h"
class Circle :public Shape
{
public:
	Circle();
	~Circle();
	virtual void draw();
};

// Circle.cpp
#include "Circle.h"
#include <iostream>
using namespace std;

Circle::Circle()
{
}


Circle::~Circle()
{
}

void Circle::draw()
{
	cout << "Circle::draw()\n";
}

// Square.h
#pragma once
#include "Shape.h"
class Square :
	public Shape
{
public:
	Square();
	~Square();
	virtual void draw();
};

// Square.cpp
#include "Square.h"
#include <iostream>
using namespace std;


Square::Square()
{
}


Square::~Square()
{
}

void Square::draw()
{
	cout << "Square::draw()\n";
}

// Rectangle.h
#pragma once
#include "Shape.h"
class Rectangle :
	public Shape
{
public:
	Rectangle();
	~Rectangle();
	virtual void draw();
};


// Rectangle.cpp
#include "Rectangle.h"
#include <iostream>
using namespace std;


Rectangle::Rectangle()
{
}


Rectangle::~Rectangle()
{
}

void Rectangle::draw()
{
	cout << "Rectangel::draw()\n";
}

// ShapeFatory.h
#pragma once
enum ShapeType
{
	Circle_Type,
	Square_Type,
	Rectangle_Type
};
class Shape;

class ShapeFatory
{
public:
	ShapeFatory();
	~ShapeFatory();
	Shape *getShape(ShapeType shapeType);
};


// ShapeFatory.cpp
#include "ShapeFatory.h"
#include "Shape.h"
#include "Circle.h"
#include "Rectangle.h"
#include "Square.h"


ShapeFatory::ShapeFatory()
{
}


ShapeFatory::~ShapeFatory()
{
}

Shape * ShapeFatory::getShape(ShapeType shapeType)
{
	Shape *pShape = nullptr;
	switch (shapeType)
	{
	case Circle_Type:
		pShape =  new Circle();
		break;
	case Square_Type:
		pShape = new Square();
		break;
	case Rectangle_Type:
		pShape = new Rectangle();
		break;
	default:
		break;
	}
	return pShape;
}#include "ShapeFatory.h"
#include "Shape.h"
#include "Circle.h"
#include "Rectangle.h"
#include "Square.h"


ShapeFatory::ShapeFatory()
{
}


ShapeFatory::~ShapeFatory()
{
}

Shape * ShapeFatory::getShape(ShapeType shapeType)
{
	Shape *pShape = nullptr;
	switch (shapeType)
	{
	case Circle_Type:
		pShape =  new Circle();
		break;
	case Square_Type:
		pShape = new Square();
		break;
	case Rectangle_Type:
		pShape = new Rectangle();
		break;
	default:
		break;
	}
	return pShape;
}


//  main.cpp
#include <iostream>

#include "Circle.h"
#include "Rectangle.h"
#include "Square.h"
#include "ShapeFatory.h"
#include <memory>
using namespace std;

void main()
{
	ShapeFatory * pShapeFactory = new ShapeFatory;// 创建工厂类对象
	
	Shape *p1 = pShapeFactory->getShape(Circle_Type);// 调用统一接口创建Circle类
	p1->draw();// 实际调用circle类的画图方法

	Shape *p2 = pShapeFactory->getShape(Square_Type);
	p2->draw();

	Shape *p3 = pShapeFactory->getShape(Rectangle_Type);
	p3->draw();

	delete p1;
	delete p2;
	delete p3;
	delete pShapeFactory;
	
	int a;
	cin >> a;
}

Résultat du programme:

Cercle :: draw ()
Place :: draw ()
Rectangel :: draw ()