include cstdlib include iostream include stdexcept include cmath inclu

#include <cstdlib>
#include <iostream>
#include <stdexcept>
#include <cmath>
#include <cstring>

template<typename T, unsigned int MAX_SIZE>
class Queue {
protected:
	T array[MAX_SIZE];
	unsigned int size;
	unsigned int start;
	unsigned int end;
public:
	void enqueue(T val) {
		if (size < MAX_SIZE) {
			if (size > 0) end = end < (MAX_SIZE - 1) ? ++end : 0;
			size++;
			array[end] = val;
		} else throw std::overflow_error("Queue is full");
	}

	T dequeue() {
		if (size > 0) {
			T result = array[start];
			size--;
			start = start < (MAX_SIZE - 1) ? ++start : 0;
			return result;
		} else throw std::underflow_error("Queue is empty");
	}
	
	void clear() {
		memset(array, MAX_SIZE, sizeof(T));
		size = 0;
		start = 0;
		end = 0;
	}
	
	unsigned int length() {
		return size;
	}
	
	Queue() {
		clear();
	}
};

int main() {
	Queue<int, 1000> q;
	int i;
	try {
		q.enqueue(123);
		q.enqueue(456);
		q.enqueue(789);
		std::cout << "manual test:";
		std::cout << q.dequeue();
		std::cout << q.dequeue();
		std::cout << q.dequeue() << std::endl;
		std::cout << "length: " << q.length() << std::endl;

		q.clear();			
		for(i = 0; i < 900; i++) q.enqueue(rand() % 1000);
		std::cout << q.length() << std::endl;
		for(i = 0; i < 500; i++) q.dequeue();
		std::cout << q.length() << std::endl;
		for(i = 0; i < 500; i++) q.enqueue(rand() % 1000);
		std::cout << q.length() << std::endl;
	} catch (std::exception &e) {
		printf("Exception thrown: %s\n", e.what()); 
	}
	
	return 0;
}