数据结构（链式队列）

数据结构

队列
队列和栈很相似，都是一种顺序表，链表；不过栈的特性为先进后出，而队列的特性为先进先出，且在生活中用处很多，比如说排号系统，银行的叫号系统都是用先进先出的特性完成的

链式队列

一、定义链式队列

Ps：用链表来实现队列

typedef int ElemType;

typedef struct Node           //链表
{
	ElemType data;
	Node *next;
}*NodePtr;

typedef struct LinkQue        //队列
{
	NodePtr front;
	NodePtr rear;
}*LinkQuePtr;

二、链式队列所实现的功能
1.链式队列初始化

int Init_LinkQue(LinkQuePtr que)        //初始化
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   Init is error\n",__FILE__,__LINE__);
		exit(0);
	}
	que->front = que->rear = NULL;
	return true;
}

2.入队列

int Push_LinkQue(LinkQuePtr que,ElemType val)       //入队列
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   Push is error\n",__FILE__,__LINE__);
		exit(0);
	}
	NodePtr s = Apply_Node(val);
	if(Empty_LinkQue(que))
	{
		que->front = s;
		que->rear = s;
	}
	else
	{
		que->rear->next = s;
		que->rear = s;
	}
	return true;
}

3.出队列

int Pop_LinkQue(LinkQuePtr que)       //出队列
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   Pop is error\n",__FILE__,__LINE__);
		exit(0);
	}
	if(Empty_LinkQue(que))
	{
		return false;
	}
	NodePtr s = que->front;
	que->front = s->next;
	free(s);
	return true;
}

4.获得队列头元素

ElemType Get_QueHead(LinkQuePtr que)       //获得队头元素
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   GetHead is error\n",__FILE__,__LINE__);
		exit(0);
	}

	if(Empty_LinkQue(que))
	{
		return false;
	}
	else
	{
		return que->front->data;
	}
}

5.申请新空间

static NodePtr Apply_Node(ElemType val)        //申请空间
{
	NodePtr s = (NodePtr)malloc(sizeof(Node));
	assert(s!=NULL);
	s->data = val;
	s->next = NULL;
	return s;
}

6.销毁链式队列

int Destroy_LinkQue(LinkQuePtr que)        //销毁
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   Destroy is error\n",__FILE__,__LINE__);
		exit(0);
	}

	if(Empty_LinkQue(que))
	{
		return false;
	}
	else
	{
		while(que->front->next!=NULL)
		{
			Pop_LinkQue(que);
		}
		que->front = que->rear = NULL;
		return true;
	}
}

7.判空

int Empty_LinkQue(LinkQuePtr que)        //判空
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   IsEmpty is error\n",__FILE__,__LINE__);
		exit(0);
	}

	if(que->front == NULL)
	{
		return true;
	}
	return false;
}

总代码：

#include <stdio.h>
#include <stdlib.h>
#include <assert.h> 

typedef int ElemType;

typedef struct Node
{
	ElemType data;
	Node *next;
}*NodePtr;

typedef struct LinkQue
{
	NodePtr front;
	NodePtr rear;
}*LinkQuePtr;

static NodePtr Apply_Node(ElemType val)
{
	NodePtr s = (NodePtr)malloc(sizeof(Node));
	assert(s!=NULL);
	s->data = val;
	s->next = NULL;
	return s;
}

int Empty_LinkQue(LinkQuePtr que)
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   IsEmpty is error\n",__FILE__,__LINE__);
		exit(0);
	}

	if(que->front == NULL)
	{
		return true;
	}
	return false;
}

int Init_LinkQue(LinkQuePtr que)
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   Init is error\n",__FILE__,__LINE__);
		exit(0);
	}
	que->front = que->rear = NULL;
	return true;
}

int Push_LinkQue(LinkQuePtr que,ElemType val)
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   Push is error\n",__FILE__,__LINE__);
		exit(0);
	}
	NodePtr s = Apply_Node(val);
	if(Empty_LinkQue(que))
	{
		que->front = s;
		que->rear = s;
	}
	else
	{
		que->rear->next = s;
		que->rear = s;
	}
	return true;
}

int Pop_LinkQue(LinkQuePtr que)
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   Pop is error\n",__FILE__,__LINE__);
		exit(0);
	}
	if(Empty_LinkQue(que))
	{
		return false;
	}
	NodePtr s = que->front;
	que->front = s->next;
	free(s);
	return true;
}

ElemType Get_QueHead(LinkQuePtr que)
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   GetHead is error\n",__FILE__,__LINE__);
		exit(0);
	}

	if(Empty_LinkQue(que))
	{
		return false;
	}
	else
	{
		return que->front->data;
	}
}

int Destroy_LinkQue(LinkQuePtr que)
{
	assert(que != NULL);
	if(que == NULL)
	{
		printf("%s:%d   Destroy is error\n",__FILE__,__LINE__);
		exit(0);
	}

	if(Empty_LinkQue(que))
	{
		return false;
	}
	else
	{
		while(que->front->next!=NULL)
		{
			Pop_LinkQue(que);
		}
		que->front = que->rear = NULL;
		return true;
	}
}

int main()
{
	//以下为测试内容-------------------
	LinkQue que;
	Init_LinkQue(&que);
	for(int i=0;i<10;i++)
	{
		Push_LinkQue(&que,i);
	}
	printf("%d  ",Get_QueHead(&que));
	//printf("%d\n",que.front->data);
	Pop_LinkQue(&que);
	printf("%d  ",Get_QueHead(&que));
	//printf("%d\n",que.front->data);
	Pop_LinkQue(&que);
	printf("%d  ",Get_QueHead(&que));
	Pop_LinkQue(&que);
	printf("%d  ",Get_QueHead(&que));
	Pop_LinkQue(&que);
	printf("%d  ",Get_QueHead(&que));
	Pop_LinkQue(&que);
	printf("%d  ",Get_QueHead(&que));
	return 0;
}