数据结构：队列

#include<iostream>

#include<cstring>

#include<stdlib.h>

#include<stdio.h>

using namespace std;

//定义结点

typedef struct _Node

{
int data;
struct _Node *next;

}node;

//定义队列

typedef struct _Queue

{
//node表示元素，queue表示队列
node *front;
node *rear;

}MyQueue;

//首先构造一个空的队列

MyQueue *CreateMyQueue()

{
MyQueue *q = (MyQueue *)malloc(sizeof(MyQueue));
q->front = NULL;
q->rear = NULL;
return q;

}

//入队

//队列是结点和队列的关系

_Queue *enQueue(MyQueue *q, int data)//无返回

{
node *newP = NULL;;//结点
newP = (node *)malloc(sizeof(node));
newP->data = data;
newP->next = NULL;
//q->front和q->rear一直是队首，队尾指针，对应了的。
if (q->front == NULL)
{
q->front = q->rear = newP;
}
else
{
q->rear->next = newP;
q->rear = newP;
}
return q;

}

void print(MyQueue *q)

{
node *dP = q->front;//结点
if (NULL == dP)//首针不指向同一位置（不为空）
{
cout << "Queue is NULL!" << endl;
return;; 
}
cout << "data:";
while (dP != q->rear)
{
cout << dP->data;
cout << "--";
dP = dP->next;
}
cout << dP->data<<endl;//打印队尾，此时，dP->next不能继续那么赋值

}

_Queue *delQueue(MyQueue *q,int i)//出栈是从队首出

{
int x=0;
node *dQ = NULL;;//结点
node *dP = q->front;//结点
if (NULL == dP)//（不为空）
{
cout << "Queue is NULL!" << endl;
return q;
}
while (x<i)
{
if (dP == q->rear)
{
cout << "队列没有那么长！" << endl;
return q;
}
++x;
dP = dP->next;
}
q->front = dP;
return q;

}

int main(int argc, int *argv[])

{
int len = 0;//队列的长
int com=1;
int choice;
MyQueue *hp = CreateMyQueue(); //定义队列
while (com)
{
cout << "please enter the number of command" << endl;
cin >> choice;
switch (choice)
{
case 1:
enQueue(hp, 1);//入队
enQueue(hp, 2);
enQueue(hp, 3);
enQueue(hp, 4);
break;
case 2:
//先定义需要插入的序号和值
print(hp);
break;
case 3:
cout << "请输入要删除多少个结点" << endl;
cin >> com;
delQueue(hp, com);
}
cout << "If you want to exit,enter '0'" << endl;
cin >> com;
}
return 0;

}