LinkedQueue.h 

#ifndef LINKEDQUEUE_H
#define LINKEDQUEUE_H

#include<iostream>
#include"../T2/LinkedList.h"
#include"Queue.h"
using namespace std;

template<typename T>
class LinkedQueue:public Queue<T>{
public:
    LinkedQueue():rear(NULL),front(NULL){}
    ~LinkedQueue(){makeEmpty();}
    bool EnQueue(const T &x);
    bool DeQueue(T &x);
    bool getFront(T &x);
    void makeEmpty();
    bool IsEmpty() const;
    bool IsFull() const{return false;}
    int getSize() const;
    friend ostream& operator<<(ostream& os,LinkedQueue& queue){
        LinkNode<T> *current = queue.front;
        while(NULL!=current){
            os << current->data << " ";
            current = current->link;
        }
        os << endl;
        return os;
    }
protected:
    LinkNode<T> *front,*rear;
};
#endif // LINKEDQUEUE_H


LinkedQueue.cpp 

#include"LinkedQueue.h"

template<typename T>
bool LinkedQueue<T>::EnQueue(const T &x)
{
    if(IsEmpty()){
        front = rear = new LinkNode<T>(x);
        if(NULL==front)
            return false;
    }else{
        rear->link = new LinkNode<T>(x);
        if(NULL==rear->link)
            return false;
        rear = rear->link;
    }
    return true;
}

template<typename T>
bool LinkedQueue<T>::DeQueue(T &x)
{
    if(IsEmpty()){
        return false;
    }
    LinkNode<T>* del = front;
    x = del->data;
    front = front->link;
    delete del;
    return true;
}

template<typename T>
bool LinkedQueue<T>::getFront(T &x)
{
    if(IsEmpty()){
        return false;
    }
    x = front->data;
    return true;
}

template<typename T>
void LinkedQueue<T>::makeEmpty()
{
    LinkNode<T> *del;
    while(front!=NULL){
        del = front;
        front = front->link;
        delete del;
    }
}

template<typename T>
bool LinkedQueue<T>::IsEmpty() const
{
    return front==NULL?true:false;
}

template<typename T>
int LinkedQueue<T>::getSize() const
{
    LinkNode<T> *current = front;
    int i = 0;
    while(NULL!=current){
        i++;
        current = current->link;
    }
    return i;
}

int main()
{
    LinkedQueue<int> queue;
    int num=0;
    for(int i=0;i<10;++i){
        num++;
        queue.EnQueue(num);
    }
    cout << queue;
    for(int j=1;j<5;++j){
        queue.DeQueue(num);
    }
    cout << queue;
    queue.getFront(num);
    cout << "front:" << num << ",size:" << queue.getSize() << endl;
}

1 2 3 4 5 6 7 8 9 10 
5 6 7 8 9 10 
front:5,size:6