队列——链式队列

  1 #include "stdafx.h"
  2 #include "stdlib.h"
  3 #include <stdio.h>
  4 #include <iostream>
  5 using namespace std;
  6 
  7 #define TRUE 1
  8 #define FALSE 0
  9 #define OK 1
 10 #define ERROR 0
 11 #define INFEASIBLE -1
 12 #define OVERFLOW -2
 13 #define QUEUEEMPTY -3
 14 
 15 
 16 typedef int Status;
 17 typedef int ElemType;
 18 
 19 typedef struct LNode{
 20     ElemType data;
 21     struct LNode* next;
 22 }LNode,*LinkList;
 23 
 24 typedef struct queue{
 25     LinkList front;
 26     LinkList rear;
 27 }QUEUE;
 28 
 29 void InitQueue(QUEUE *Q);
 30 void EnQueue(QUEUE *Q,ElemType elem);
 31 void DeQueue(QUEUE *Q,ElemType *elem);
 32 void GetFront(QUEUE Q,ElemType *elem);
 33 bool QueueEmpty(QUEUE Q);
 34 int FreeQueue(QUEUE Q);
 35 
 36 //初始化队列
 37 void InitQueue(QUEUE *Q)
 38 {
 39     Q->front = (LinkList)malloc(sizeof(LNode));
 40     if(Q->front == NULL) exit(ERROR);
 41     Q->rear = Q->front;
 42 }
 43 
 44 //入队
 45 void EnQueue(QUEUE *Q,ElemType elem)
 46 {
 47     LinkList s;
 48     s = (LinkList)malloc(sizeof(LNode));
 49     if(!s) exit(ERROR);
 50     s->data = elem;
 51     s->next = NULL;
 52     Q->rear->next = s;
 53     Q->rear = s;
 54 }    
 55  
 56 //出队
 57 void DeQueue(QUEUE *Q,ElemType *elem)
 58 {
 59     LinkList s;
 60     if(QueueEmpty(*Q)) exit(ERROR);
 61     *elem = Q->front->next->data;
 62     s = Q->front->next;
 63     Q->front->next = s->next;
 64     free(s);
 65 }
 66 
 67 //获取队头元素内容
 68 void GetFront(QUEUE Q,ElemType *elem)
 69 {
 70     if(QueueEmpty(Q)) exit(ERROR);
 71     *elem = Q.front->next->data;
 72 }
 73 
 74 //判断队列Q是否为空
 75 bool QueueEmpty(QUEUE Q)
 76 {
 77     if(Q.front == Q.rear) return TRUE;
 78     return FALSE;
 79 }
 80 
 81 //释放队列
 82 int FreeQueue(QUEUE *Q)
 83 {
 84     while(Q->front)
 85     {
 86         Q->rear = Q->front->next;
 87         free(Q->front);
 88         Q->front = Q->rear;
 89     }
 90     return OK;
 91 }
 92 
 93 int _tmain(int argc, _TCHAR* argv[])
 94 {
 95     QUEUE Q;
 96     InitQueue(&Q);
 97     EnQueue(&Q,1);
 98     EnQueue(&Q,2);
 99     ElemType e;
100     DeQueue(&Q,&e);
101     cout <<"De queue:"<<e;
102     
103     FreeQueue(&Q);
104 
105     DeQueue(&Q,&e);
106     cout <<"De queue:"<<e;
107     system("pause");
108     return 0;
109 }