数据结构之队列

#include <iostream>
#include <cstdio>
#include <stdlib.h>


using namespace std;

namespace Queue{
    template<typename Q>
    class queue{
        typedef Q * ptr;
        public:
            ptr que;
            int len;
            int size;
            int head;
            int tail;
            queue(){
                this->len = 0;
                this->head = 0;
                this->tail = 0;
                this->size = 0;
                que = new Q[1000];
            }
            queue(int len):len(len + 1)
            {
                this->head = 0;
                this->tail = 0;
                this->size = 0;
                que = new Q[len];
            }

            bool empty()
            {
                return !size;
            }

            int length()
            {
                return size;
            }

            Q front()
            {
                return que[head];
            }

            void insert(Q e)
            {
                if ( size >= len ){
                    cout << "full queue !!!" <<endl;
                    exit(-1);
                }
                else{
                    que[tail] = e;tail = (tail + 1) % len;
                    size++;
                }
            }
            Q pop()
            {
                if (!size) {
                    cout << "empty queue !!!" <<endl;
                    exit(-1);
                } 
                else{
                    ptr  tmp = &que[head];
                    head = (head + 1) % len;
                    size--;
                    return *tmp;
                }
            }

            void iterator(void(*visit)(Q e))
            {
                for (int i = head;i!=tail;i = (i + 1)%len)
                {
                    visit(que[i]);
                }
                cout << "-----------------" << endl;
            }
    };
}

void visit(int d)
{
    cout << d << endl;
}

int main()
{
    Queue::queue<int> q(5);
    q.insert(9);
    q.insert(10);
    q.insert(11);
    q.insert(8);
    q.insert(1);
    q.iterator(visit);
    while(!q.empty())
    {
        cout <<q.pop() <<endl;
    }
    cout << q.size <<endl;
    return 0;
}