【QIUC】第一卷-C/C++高级（十）- 练习二

文章目录

【QIUC】第一卷-C/C++高级（十）- 练习二

问题：

定义一个或多个类，来描述以下需求：
汽车：有多个轮胎，一个发动机，品牌，型号, 价格，行驶里程。
轮胎：有品牌，尺寸，气压。
发动机：有品牌，型号。

源码：

第一种：

Tires.h

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

class Tires
{
    
    
public:
	Tires(string brand, int size, int pressure);

	string getBrand()const;
	int getSize()const;
	int getPressure()const;
	string descripition()const;

	static void inPuttires(vector<Tires>&tires);


private:
	string brand;
	int size;
	int pressure;

};

Tires.cpp

#include <string>
#include <sstream>
#include <iostream>
#include "Tires.h"

using namespace std;

Tires::Tires(string brand, int size, int pressure) {
    
    
	this->brand = brand;
	this->size = size;
	this->pressure = pressure;
}

string Tires::getBrand()const {
    
    
	return brand;
}

int Tires::getSize()const {
    
    
	return size;
}

int Tires::getPressure()const {
    
    
	return pressure;
}

string Tires::descripition() const
{
    
    
	stringstream ret;
	ret << "轮胎的品牌：" << brand << " " << "轮胎的尺寸：" << size << " "
		<< "轮胎的气压：" << pressure << endl;
	return ret.str();
}

void Tires::inPuttires(vector<Tires>& tires)
{
    
    
        int n = 1;
        string brand;
        int size;
        int pressure;


        while (1) {
    
    
            cout << "请输入第" << n << "个的品牌：（输入0结束）";
            cin >> brand;
            if (brand == "0") {
    
    
                break;
            }
            cout << "请输入第" << n << "个的尺寸：";
            cin >> size;


            cout << "请输入第" << n << "个的气压：";
            cin >> pressure;


            Tires tires1(brand, size, pressure);
            tires.push_back(tires1);
            //tires.push_back(Tires(brand,size,pressure));可以
            //tires.push_back(&tires1);错误
            n++;
        }


    }

Engine.h

#pragma once
#include <string>

using namespace std;

class Engine
{
    
    
public:
	Engine(string brand,string model);

	string getBrand()const;
	string getModel()const;


private:
	string brand;
	string model;
};

Engine.cpp

#include "Engine.h"

Engine::Engine(string brand, string model)
{
    
    
	this->brand = brand;
	this->model = model;
}

string Engine::getBrand() const
{
    
    
	return brand;
}

string Engine::getModel() const
{
    
    
	return model;
}

Car.h

#pragma once
#include <string>
#include <vector>
#include "Engine.h"
#include "Tires.h"

using namespace std;

class Car
{
    
    
public:
	Car(string  brand,string model,int price,unsigned int distance,string engBrand,string ensModel);
	

	string getBrand()const;
	string getMoedl()const;
	int getPrice()const;
	unsigned int getDistance()const;
    vector<Tires*> getTires()const;
	string descripition()const;
	
	void addTires(Tires &other);


private:
    string  brand;
	string model;
	int price;
	unsigned int distance;
	Engine *engine;
	vector<Tires*>tires;


};

Car.cpp

#include <string>
#include <vector>
#include <sstream>
#include "Car.h"

using namespace std;

Car::Car(string  brand, string model, int price, unsigned int distance,string engBrand, string ensModel) {
    
    
	this->brand = brand;
	this->model = model;
	this->price = price;
	this->distance = distance;
	this->engine = new Engine(engBrand, ensModel);
}

string Car::getBrand()const {
    
    
	return brand;
}

string Car::getMoedl()const {
    
    
	return model;
}

int Car::getPrice()const {
    
    
	return price;
}

unsigned int Car::getDistance()const {
    
    
	return distance;
}

string Car::descripition() const
{
    
    
	stringstream ret;
	ret << "品牌：" << brand << " " << "型号：" << model << " " << "价格：" << price          << " "<< "里程：" << distance << " " << "发动机品牌：" << engine->getBrand() <<        " "<< "发动机型号：" << engine->getModel() << endl;

	return ret.str(); 
}

vector<Tires*> Car::getTires() const
{
    
    
	return tires;
}

void Car::addTires(Tires& other)
{
    
    
	tires.push_back(&other);
}

说明：

使用**void Tires::inPuttires(vector& tires)**函数时
1. 这个函数可以说同时包含了
  
  vector<Tires> Car::getTires() const*
  {
  return tires;
  }
  
  void Car::addTires(Tires& other)
  {
  tires.push_back(&other);
  }
  
  这两个函数的功能使得最后的返回值都不需要，直接对在主函数中定义的容器进行操作。
2. 若这个函数的声明是这样的void Tires::inPuttires vector<Tires*>& tires) 那么在后面使用push_back 函数时
  1. tires.push_back(&Tires(brand,size,pressure));
  这样会出错，&符号要求是一个左值
  1. Tires tires1(brand, size, pressure);
    tires.push_back(&tires1) 这样的话，由于我们始终都是使用一个tires1来作为载体，传递的始终都是他的地址，那样的话，访问的时候就会出错
还要注意的是当engine是指针或者实例时而选择箭头后者点号，组合和聚合的注意事项参考文档
这里说明一下改进方法：一是把engine改为不是指针，加上默认构造函数；二是Tire不使用容器，直接使用对象数组，这样才能更进一步表明两者是一种组合的方式与Car结合的。

第二种

Tire.h

#pragma once
#include <string>

using namespace std;

class Tire
{
    
    
public:
	Tire(const string &brand="米其林");
	~Tire();
	string descripton() const;
	string getBrand() const;
	float getPressure() const;

private:
	string brand;		
	float pressure;   
};

Tire.cpp

#include "Tire.h"
#include <sstream>



Tire::Tire(const string &brand)
{
    
    
	this->brand = brand;
	this->pressure = 2.5; 
}


Tire::~Tire()
{
    
    
}

string Tire::descripton() const
{
    
    
	stringstream ret;
	ret << "品牌:" << brand  << "-胎压:" << pressure;
	return ret.str();
}

string Tire::getBrand() const
{
    
    
	return brand;
}

float Tire::getPressure() const
{
    
    
	return pressure;
}

Engine.h

#pragma once
#include <string>

using namespace std;

class Engine
{
    
    
public:
	Engine();
	Engine(const string &brand,  float version);
	~Engine();

	string description() const;

private:
	string brand;		
	float version;		
};

Engine.cpp

#include <sstream>
#include "Engine.h"



Engine::Engine()
{
    
    
}

Engine::Engine(const string & brand, float version)
{
    
    
	this->brand = brand;
	this->version = version;
}


Engine::~Engine()
{
    
    
}

string Engine::description() const
{
    
    
	stringstream ret;
	ret << "品牌:" << brand << "-型号:" << version;
	return ret.str();
	
}

Car.h

#pragma once
#include <string>
#include "Engine.h"
#include "Tire.h"

using namespace std;

class Car
{
    
    
public:
	Car();
	Car(const string &carBrand, const string &carVer, int carPrice,
		const string &engineBrand, float engineVer,
		const string &tireBrand = "米其林");
	~Car();

	Engine getEngine();
	Tire* getTire(int i);
	string getBrand();
	string getVersion();
	int getPrice();
	int getMiles();
	string description();

private:
	Engine engine;
	Tire  tires[4];
	string brand;  //品牌
	string version; //型号
	int price;
	int miles;
};

Car.cpp

#include <sstream>
#include "Car.h"


Car::Car()
{
    
    
}

Car::Car(const string & carBrand, const string & carVer, int carPrice, 
	const string & engineBrand, float engineVer, 
	const string & tireBrand):
	engine(engineBrand, engineVer), tires{
    
     tireBrand, tireBrand, tireBrand, tireBrand }
{
    
    
	this->brand = carBrand;
	this->price = carPrice;
	this->version = carVer;
	this->miles = 0;
}


Car::~Car()
{
    
    
}

Engine Car::getEngine()
{
    
    
	return engine;
}

Tire* Car::getTire(int i)
{
    
    
	if (i>=1 && i<=4) {
    
    
		return &tires[i];
	}

	return NULL;
}

string Car::getBrand()
{
    
    

	return brand;
}

string Car::getVersion()
{
    
    
	return version;
}

int Car::getPrice()
{
    
    
	return price;
}

int Car::getMiles()
{
    
    
	return miles;
}

string Car::description()
{
    
    
	stringstream ret;
	ret << "汽车品牌:" << brand << "-" << version << "-$" << price
		<< "\t\t引擎:" << engine.description()
		<< "\t\t轮胎:" << tires[0].descripton();

	return ret.str();
}

main.cpp

#include <iostream>
#include <Windows.h>
#include "Car.h"

int main(void) {
    
    
	{
    
    
		Car car("宝马", "X7", 950000, "宝马", 3.5);
		cout << car.description() << endl;
	}

	system("pause");
	
	return 0;

说明：

这里的 Engine 和 Tire 都要使用组合的方式，所以第一种的方式有待改进
在 Engine 和 Tire 中都定义一个description函数的目的是在后面Car的description函数中不需要一个一个的调用获取函数，只需要一次即可
由于在Car函数中的定义是Tire tires[4] 所以在初始化列表中需要的操作不一样：

Car::Car(const string & carBrand, const string & carVer, int carPrice,
const string & engineBrand, float engineVer,
const string & tireBrand):
engine(engineBrand, engineVer), tires{ tireBrand, tireBrand, tireBrand, tireBrand }

根据类比，如果Tire需要多个参数，那么需要在外面加一个括号。

【QIUC】第一卷-CC++高级（十）- 练习二

【QIUC】第一卷-C/C++高级（十）- 练习二

文章目录

问题：

源码：

第一种：

第二种

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