Queue.cpp

//  
//  algorithm - some algorithms in "Introduction to Algorithms", third edition
//  Copyright (C) 2018  lxylxy123456
//  
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU Affero General Public License as
//  published by the Free Software Foundation, either version 3 of the
//  License, or (at your option) any later version.
//  
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Affero General Public License for more details.
//  
//  You should have received a copy of the GNU Affero General Public License
//  along with this program.  If not, see <https://www.gnu.org/licenses/>.
//  

#ifndef MAIN
#define MAIN
#define MAIN_Queue
#endif

#ifndef FUNC_Queue
#define FUNC_Queue

#include <exception>
#include "utils.h"

template <typename T>
class Queue {
	public:
		Queue(size_t size): head(0), tail(0), length(size), data(new T[size]) {}
		void Enqueue(T x) {
			data[tail++] = x; 
			if (tail == length)
				tail = 0; 
			if (tail == head)
				throw std::invalid_argument("overflow");
		}
		T Dequeue() {
			if (head == tail)
				throw std::invalid_argument("underflow"); 
			T& ans = data[head++]; 
			if (head == length)
				head = 0; 
			return ans; 
		}
		bool Empty() {
			return head == tail; 
		}
		~Queue() { delete [] data; }
	private:
		size_t head, tail, length; 
		T* data; 
}; 
#endif

#ifdef MAIN_Queue
int main(int argc, char *argv[]) {
	const size_t n = get_argv(argc, argv, 1, 16); 
	Queue<int> S(n); 
	std::cout << "d: dequeue" << std::endl; 
	std::cout << "e: enqueue" << std::endl; 
	std::cout << "E: empty" << std::endl; 
	std::cout << "q: quit" << std::endl; 
	while (true) {
		char c; int x; 
		std::cout << ">> "; 
		if (!(std::cin >> c)) {
			std::cout << std::endl; 
			break; 
		}
		switch (c) {
			case 'e': 
				std::cout << "x = "; 
				std::cin >> x; 
				S.Enqueue(x); 
				break; 
			case 'd': 
				std::cout << S.Dequeue() << std::endl; 
				break; 
			case 'E': 
				std::cout << std::boolalpha << S.Empty() << std::endl; 
				break; 
			case 'q': 
				return 0; 
		}
	}
	return 0; 
}
#endif