Common means of modeling: combination

Combine

• explain ： Combination and aggregation , No C++ The grammar requirements of , It is a common means in application .

• demand ：
  Build a computer class , A computer , from CPU chip , Hard disk , Memory, etc .
  CPU Chips also use classes to represent .

 
CPU.h

#pragma once
#include <string>
using namespace std;

class Cpu{
    
public:
	Cpu(string brand = "Inter", string model = "i5");
	~Cpu();
private:
	string brand;	// brand 
	string model;	// model 
};

 

CPU.cpp

#include "Cpu.h"
#include <iostream>

Cpu::Cpu(string brand, string model){
    
	this->brand = brand;
	this->model = model;
	cout << "Cpu  Start " << endl;
}

Cpu::~Cpu(){
    
	cout << "Cpu  end " << endl;
}

 
Computer.h

#pragma once
#include <string>
#include <iostream>
#include <Windows.h>
#include "Cpu.h"
using namespace std;

class Computer{
    
public:
	Computer(string cpuBrand, string cpuModel, int hardDisk, int memory);
	~Computer();
private:
	Cpu cpu;		//Cpu Classes and Computer Between classes ,  Namely " Combine "
	//Cpu *cpu; // Pointer mode 
	int hardDisk;	// Hard disk 
	int memory;		// Memory 
};

 
Computer.cpp

#include "Computer.h"
//cpu The parameters of are initialized with a list 
Computer::Computer(string cpuBrand, string cpuModel, 
	int hardDisk, int memory) : cpu(cpuBrand, cpuModel)
{
    
	// Initialize with pointer 
	//this->cpu = new Cpu(cpuBrand, cpuModel);
	this->hardDisk = hardDisk;
	this->memory = memory;
	cout << " Computer   Start " << endl;
}

Computer::~Computer(){
    
	// Pointer free memory  
	//delete cpu;
	cout << " Computer   end " << endl;
}

 
main.cpp

#include "Computer.h"

using namespace std;
void test() {
    
	Computer computer(" Intel ", "i9 11900k", 512, 32);
}

int main(void) {
    
	// When test At the end of the function 
	// Computers and Cpu Will be completely destroyed 
	test();

	system("pause");
	return 0;
}

 

 

Summary ：
The object of being owned （cpu chip ） Its life cycle and its owner （ Computer ） The life cycle of is consistent .
When the computer is created ,cpu The chip is also created .
When the computer is destroyed ,cpu The chip is also destroyed .
The owner needs to be responsible to the owner , It's a strong relationship , It's the relationship between the whole and the part .

Specific combination mode ：
1） The combined object directly uses the member object .（ Commonly used ）
2） Use pointers to represent the combined objects , In the constructor , Create combined objects ; In destructors , Release the combined objects .
 
 
UML The combination in represents ：

Note that the inclusion uses a solid diamond
【 Add 】UML drawing tools ：starUML