【基本数据结构】(循环)队列/queue/FIFO

类模板

#pragma once
#include <iostream>
#include <cassert>

template <typename Type, int MAXSIZE>
class queue//FIFO context
{
	//Elements are pushed into the "back_" of the specific container
	//and popped from its "front_".
private:
	Type* info;
	int front_, back_;//Emements from (front_ + 1) to back_;
	int count;
public:
	queue(){
		info = new Type[MAXSIZE];
		front_ = 0;	back_ = 0;
		count = 0;
	}
	~queue(){
		delete[] info;
	}
	bool empty(){
		return !count;
	}
	int size(){
		return count;
	}
	Type front(){
		assert(count);
		return info[(front_ + 1) % MAXSIZE];
	}
	Type back(){
		assert(count);
		return info[back_];
	}
	void push_back(Type ins){
		assert(count < MAXSIZE);
		count++;
		back_ = (back_ + 1) % MAXSIZE;
		info[back_] = ins;
		
	}
	void pop_front(){
		assert(count);
		front_ = (front_ + 1) % MAXSIZE;
		count--;
	}
};

ACM简单实现

const int MAXSIZE = 10;
int info[MAXSIZE], l = 0, r = 0, ele = 0;//Elements from (l + 1) to r;
inline int putin(int ins) {
	ele++;
	r = (r + 1) % MAXSIZE;
	info[r] = ins;
}
inline int pop() { l = (l + 1) % MAXSIZE; }

STL实现

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

int main()
{
	queue<char> arr;
	arr.push('c');
	arr.push('a');
	cout << arr.empty() << endl;
	cout << arr.front() << endl;
	cout << arr.back() << endl;
	arr.pop();
	arr.push('s');
	cout << arr.empty() << endl;
	cout << arr.front() << endl;
	cout << arr.back() << endl;
	return 0;
}