猫狗队列

题目

实现一种猫狗队列的结构，具体要求可参考书本。实现同参考原书

实现过程中遇到的一些问题

首先根据书中类的设计准则，一个入队的新类型要包括当前入队的宠物类型以及入队的时间戳，在出队时要根据时间戳来依次出队。

在popDog()函数设计返回时，由于返回的需要是dog类型，可以初始化一个基类的指针指向派生类的引用，然后再可以让基类指针指向pop类型，返回结果。

代码

#include<iostream>
#include<queue>
#include<string>
using namespace std;

/*猫狗类原型*/
class Pet {
private:
	string type;
public:
	Pet() {}
	Pet(string type)
	{
		this->type = type;
	}
	string getPetType()
	{
		return this->type;
	}
};

class dog : public Pet {
public:
	dog():Pet("dog") {}
};

class cat : public Pet {
public:
	cat() :Pet("cat") {}
};

class petEnterQueue {
private:
	Pet pet1;
	long count;
public:
	petEnterQueue(Pet p, long count)
	{
		this->pet1 = p;
		this->count = count;
	}
	Pet getPet()
	{
		return this->pet1;
	}
	long getCount()
	{
		return this->count;
	}
	string getEnterPetType()
	{
		return this->pet1.getPetType();
	}
};

class catDogQueue
{
private:
	queue<petEnterQueue> dogQ;
	queue<petEnterQueue> catQ;
	long count;
public:
	catDogQueue()
	{
		this->count = 0;
	}
	void push(Pet pet);
	Pet popAll();
	dog popDog();
	cat popCat();
	bool isEmpty();
	bool isDogQueueEmpty();
	bool isCatQueueEmpty();
};

void catDogQueue::push(Pet pet)
{
	if (pet.getPetType() == "dog")
		dogQ.push(petEnterQueue(pet, this->count++));
	else if (pet.getPetType() == "cat")
		catQ.push(petEnterQueue(pet, this->count++));
	else
		printf("Error, not dog or cat!\n");
}

Pet catDogQueue::popAll()
{
	if (!dogQ.empty() && !catQ.empty())
	{
		if (dogQ.front().getCount() < catQ.front().getCount())
		{
			Pet tmp;
			tmp = dogQ.front().getPet();
			dogQ.pop();
			return tmp;
		}
		else
		{
			Pet tmp;
			tmp = catQ.front().getPet();
			catQ.pop();
			return tmp;
		}
	}
	else if (!dogQ.empty())
	{
		Pet tmp;
		tmp = dogQ.front().getPet();
		dogQ.pop();
		return tmp;
	}
	else if (!catQ.empty())
	{
		Pet tmp;
		tmp = catQ.front().getPet();
		catQ.pop();
		return tmp;
	}
	else
		printf("The catDogQueue is empty!\n");
}

dog catDogQueue::popDog()
{
	if (!dogQ.empty())
	{
		Pet tmpP;
		tmpP = dogQ.front().getPet();
		dog tmp;
		Pet* p = &tmp;
		*p = tmpP;
		dogQ.pop();
		return tmp;
	}
	else
		printf("The dogQueue is empty!\n");
}

cat catDogQueue::popCat()
{
	if (!catQ.empty())
	{
		Pet tmpP;
		tmpP = catQ.front().getPet();
		cat tmp;
		Pet *p = &tmp;
		*p = tmpP;
		catQ.pop();
		return tmp;
	}
	else
		printf("The catQueue is empty!\n");
}

bool catDogQueue::isEmpty()
{
	return catQ.empty() && dogQ.empty();
}

bool catDogQueue::isCatQueueEmpty()
{
	return catQ.empty();
}

bool catDogQueue::isDogQueueEmpty()
{
	return dogQ.empty();
}

int main()
{
	catDogQueue cdq;
	if (cdq.isEmpty())
		cout << "The whole queue is empty!" << endl;
	cdq.push(dog());
	if (!cdq.isDogQueueEmpty())
		cout << "Dog queue is not empty!" << endl;
	if (!cdq.isCatQueueEmpty())
		cout << "Cat queue is not empty!" << endl;
	for (int i = 0; i < 2; i++)
	{
		cdq.push(cat());
		cdq.push(dog());
	}
	cout << "popAll:" << cdq.popAll().getPetType() << endl;
	cout << "popDog:" << cdq.popDog().getPetType() << endl;
	cout << "popCat:" << cdq.popCat().getPetType() << endl;
	cout << "popAll:" << cdq.popAll().getPetType() << endl;
	cout << "popAll:" << cdq.popAll().getPetType() << endl;
	if (cdq.isEmpty())
		cout << "All queue is empty!" << endl;
	getchar();
	return 0;
}