C++ 两个队列实现堆栈

//构建队列

#include<iostream>
using namespace std;
struct queuenode
{
int data;
queuenode* next;
};
class queue
{
private:
queuenode* head;
public:
queue(){head=new queuenode;head->next=NULL;}
~queue();
void push(int data);
void removenode(int data);
int pop();
void print();
};
void queue:: push(int data)
{
queuenode*p=head;
queuenode*q=new queuenode;
q->data=data;
q->next=NULL;

while(p->next!=NULL)
p=p->next;
p->next=q;

}
int queue::pop()
{
queuenode*p=head->next;
if(p==NULL)
{
cout<<"the queue is empty"<<endl;
return NULL;
}
else
{
head->next=p->next;
cout<<"出队元素："<<p->data<<endl;
return p->data;
delete p;
p=NULL;
}
}
void queue:: print()
{
queuenode*p=head;
while(p->next!=NULL)
{
cout<<p->next->data<<" ";
p=p->next;
}
cout<<endl;
}
queue::~queue()
{
queuenode*p;
while (head->next)
{
p = head;
head = head->next;
delete p;
}
delete head;
head=NULL;
p=NULL;
}
int main()
{
queue queue1;
queue queue2;
queue1.push (1);
queue1.push (2);
queue1.push (3);
queue1.push (4);
queue1.push (5);
queue1.print();
queue2.push(queue1.pop());
queue2.push(queue1.pop());
queue2.push(queue1.pop());
queue2.push(queue1.pop());
queue1.pop();
queue2.print();
return 0;
}