队的链式结构表示

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 
  4 #define TRUE 1
  5 #define FALSE 0
  6 #define OK 1
  7 #define ERROR 0
  8 #define OVERFLOW -2
  9 
 10 typedef int QElemType;
 11 typedef int Status;
 12 
 13 /*
 14  * 存储结构
 15  */
 16 typedef struct QNode
 17 {
 18     QElemType data;
 19     struct QNode *next;
 20 }QNode, *QueuePtr;
 21 
 22 typedef struct
 23 {
 24     QueuePtr front;    //队头指针
 25     QueuePtr rear;    //队尾指针
 26 }LinkQueue;
 27 
 28 /*
 29  * 初始化队列
 30  */
 31 Status InitQueue(LinkQueue *Q)
 32 {
 33     Q->front = Q->rear = (QueuePtr) malloc(sizeof(QNode));
 34     if (!Q->front)
 35     {
 36         exit(OVERFLOW);
 37     }
 38     Q->front->next = NULL;
 39     return OK;
 40 }
 41 
 42 /*
 43  * 销毁队列
 44  */
 45 Status DestroyQueue(LinkQueue *Q)
 46 {
 47     while (Q->front)
 48     {
 49         Q->rear = Q->front->next;
 50         free(Q->front);
 51         Q->front = Q->rear;
 52     }
 53     return OK;
 54 }
 55 
 56 /*
 57  * 清空队列
 58  */
 59 Status ClearQueue(LinkQueue *Q)
 60 {
 61     DestroyQueue(Q);
 62     InitQueue(Q);
 63 }
 64 
 65 /*
 66  * 判断队列是否为空
 67  */
 68 Status IsEmpty(LinkQueue Q)
 69 {
 70     if (Q.front->next == NULL)
 71     {
 72         return TRUE;
 73     }
 74     else
 75     {
 76         return FALSE;
 77     }
 78 }
 79 
 80 /*
 81  * 获取队列的长度
 82  */
 83 int GetLength(LinkQueue Q)
 84 {
 85     int i = 0;
 86     QueuePtr p = Q.front;
 87     while (Q.rear != p)
 88     {
 89         i++;
 90         p = p->next;
 91     }
 92     return i;
 93 }
 94 
 95 /*
 96  * 获取队头元素
 97  */
 98 Status GetHead(LinkQueue Q, QElemType *e)
 99 {
100     QueuePtr p;
101     if (Q.front == Q.rear)
102     {
103         return ERROR;
104     }
105     p = Q.front->next;
106     *e = p->data;
107     return OK;
108 }
109 
110 /*
111  * 入队
112  */
113 Status EnQueue(LinkQueue *Q, QElemType e)
114 {
115     QueuePtr p = (QueuePtr) malloc(sizeof(QNode));
116     if (!p)
117     {
118         exit(OVERFLOW);
119     }
120     p->data = e;
121     p->next = NULL;
122     Q->rear->next = p;
123     Q->rear = p;
124     return OK;
125 }
126 
127 /*
128  * 出队
129  */
130 Status DeQueue(LinkQueue *Q, QElemType *e)
131 {
132     QueuePtr p;
133     if (Q->front == Q->rear)
134     {
135         return ERROR;
136     }
137     p = Q->front->next;
138     *e = p->data;
139     Q->front->next = p->next;
140     if (Q->rear == p)
141     {
142         Q->rear = Q->front;
143     }
144     free(p);
145     return OK;
146 }
147 
148 /*
149  * 访问元素
150  */
151 void visit(QElemType e)
152 {
153     printf("%d ", e);
154 }
155 
156 /*
157  * 遍历队列
158  */
159 Status TraverseQueue(LinkQueue Q, void (*visit)(QElemType))
160 {
161     QueuePtr p = Q.front->next;
162     while (p)
163     {
164         visit(p->data);
165         p = p->next;
166     }
167     return OK;
168 }
169 
170 int main()
171 {
172     LinkQueue Q;
173     if (InitQueue(&Q))
174     {
175         QElemType e;
176         int i;
177 
178         printf("init_success\n");
179 
180         if (IsEmpty(Q))
181         {
182             printf("queue is empty\n");
183         }
184 
185         for (i = 0; i < 10; i++)
186         {
187             EnQueue(&Q, i);
188         }
189 
190         GetHead(Q, &e);
191         printf("The first element is %d\n", e);
192 
193         printf("length is %d\n", GetLength(Q));
194 
195         DeQueue(&Q, &e);
196         printf("delete element is %d\n", e);
197 
198         TraverseQueue(Q, *visit);
199 
200         if (DestroyQueue(&Q))
201         {
202             printf("\ndestroy_success\n");
203         }
204     }
205 }