CC150 3.7 Solution Class

AnimalQueueSln.h.cpp

/* CC150 3.7
 * Create the data structure to mantain a animal shelter system
 * and implement operations such as enqueue, dequeueAny, dequeueDog and dequeueCat
 */

#ifndef ANIMALQUEUESLN_H
#define ANIMALQUEUESLN_H

#include <iostream>
#include <string>
#include <list>

using namespace std;

struct Animal {
	Animal() : type('\0'), name(""), age(-1) {}
	Animal(char c, string s) : type(c), name(s), age(0) {}
	Animal(char c, string s, double d) : type(c), name(s), age(d) {}
	void display();
	bool isDog() { return type == 'D'; }
	bool isCat() { return type == 'C'; }
	void setOrder(int d) { order = d; }
	int getOrder() { return order; }
private:
	char type;
	string name;
	double age;
	int order = 0;
	bool isEmpty() { return type == '\0'; }
};

void Animal::display()
{
	if (isEmpty()) return;
	cout << "No " << getOrder() << ": ";
	if (isDog()) cout << "Dog, ";
	else if (isCat()) cout << "Cat, ";
	cout << "Name is " << name << ", Age is " << age << endl;
}

class AnimalQueue {
public:
	void enqueue(Animal);
	Animal dequeueAny();
	Animal dequeueDog();
	Animal dequeueCat();
private:
	list<Animal> dogQueue;
	list<Animal> catQueue;
	int animalNumber = 0;
};

void AnimalQueue::enqueue(Animal animalIn)
{
	animalIn.setOrder(++animalNumber);
	if (animalIn.isDog())
		dogQueue.push_back(animalIn);
	else if (animalIn.isCat())
		catQueue.push_back(animalIn);
	else
		cerr << "Cannot distinguish animal type!" << endl;
}

Animal AnimalQueue::dequeueAny()
{
	if (dogQueue.empty() && catQueue.empty()) { // both queues are empty
		cerr << "No animal available!" << endl;
		return Animal();
	}
	if (dogQueue.empty()) // one of two queues is empty, dequeue the other one
		return dequeueCat();
	else if (catQueue.empty())
		return dequeueDog();
	if ((dogQueue.begin())->getOrder() < (catQueue.begin())->getOrder())
		return dequeueDog();
	else
		return dequeueCat();
}

Animal AnimalQueue::dequeueDog()
{
	if (dogQueue.empty()) {
		cerr << "No dog available!" << endl;
		return Animal();
	}
	Animal dogDeque = *dogQueue.begin();
	dogQueue.erase(dogQueue.begin());
	return dogDeque;
}

Animal AnimalQueue::dequeueCat()
{
	if (catQueue.empty()) {
		cerr << "No cat available!" << endl;
		return Animal();
	}
	Animal catDeque = *catQueue.begin();
	catQueue.erase(catQueue.begin());
	return catDeque;
}

#endif