数据结构队列例题二-链表实现

#include

using namespace std;

typedef struct QNode
{
	int data;
	struct QNode *next;
	
}QNode ,*QueuePtr;

typedef struct
{
	QueuePtr front;
	QueuePtr rear;
}LinkQueue;

void Init(LinkQueue &Q)//初始化 
{
	Q.front = Q.rear = new QNode;
	Q.rear ->next = NULL;
	
}

void EnQueue(LinkQueue &Q , int e)//插入元素 
{
	
	QueuePtr p = new QNode;
	p ->data = e;
	p ->next = NULL;
	Q.rear ->next = p;
	Q.rear = p;
	
}

void DeQueue(LinkQueue &Q , int &e) //出队 
{
	if(Q.front == Q.rear)
	{
		cout<<"队空"<<'\n';
	    return ;
	}
	QueuePtr p = new QNode;
	p = Q.front ->next;
	e = p->data;
	Q.front ->next = p ->next;
	if(Q.rear == p) Q.rear = Q.front;//若队尾元素被删除，尾节点指向头节点
	delete p; 
	
}

int GetHead(LinkQueue &Q)//取队头元素 
{
	if(Q.front != Q.rear)
	{
		return Q.front ->next ->data;
	}
	else
	{
		cout<<"队空"<<'\n';
		return 0;
	}
}

int main()
{
    LinkQueue Q;
	Init(Q);
	
    cout<<"输入数据,输入-1时停止"<<'\n';
	
	while(1)
	{ 
	 	int x;
		cin>>x; 
		if(x == -1) break; 
		EnQueue(Q,x);
	}
	
	int e = 0;
	cout<<"队头出队:";
	DeQueue(Q,e);
	cout<<e<<'\n';
	cout<<"取队头元素:"<<GetHead(Q);
	
	
}