1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #define OK 1
 4 #define ERROE 0
 5 #define OVERFLOW -2
 6 typedef int Status;
 7 typedef int QElemType;
 8 typedef struct Node
 9 {
10     QElemType data;
11     struct Node *next;
12 } QNode;
13 /* 当链式队列的头尾节点指针定义成为一个单独的结构体,避免在新增节点时占用过多的空间 */
14 typedef struct
15 {
16     QNode *front;
17     QNode *rear;
18 } LinkQueue;
19 Status InitQueue(LinkQueue *Q)
20 {
21     Q->front = Q->rear = (QNode *)malloc(sizeof(QNode));
22     if (!Q->front)
23         exit(OVERFLOW);
24     Q->rear->next = NULL; //rear.next始终指向NULL,头结点front不动
25     return OK;
26 }
27 Status InQueue (LinkQueue *Q, int elem)
28 {
29     QNode *p;
30     p = (QNode *)malloc(sizeof(QNode));
31     p->data = elem;
32     p->next = NULL;
33     Q->rear->next = p;
34     Q->rear = p;
35     return OK;
36 }
37 Status PrintQueue(LinkQueue Q)
38 {
39     QNode *p;
40     p = Q.front->next;
41     printf("the queue is:");
42     while(p != NULL)
43     {
44         printf("%d ", p->data);
45         p = p->next;
46     }
47     return OK;
48 }
49 Status OutQueue(LinkQueue *Q)
50 {
51     QNode *p;
52     int i;
53     printf("\nthe number of out queue:");
54     scanf("%d", &i);
55     while(i != 0)
56     {
57         p = Q->front;
58         Q->front = Q->front->next;
59         free(p);
60         i--;
61     }
62     p = NULL;
63     return OK;
64 }
65 Status EmptyQueue(LinkQueue Q)
66 {
67     if (Q.front->next == NULL)
68         printf("\nThe queue is empty!\n");
69     return OK;
70 }
71 int main()
72 {
73     LinkQueue queue;
74     InitQueue(&queue);
75     int elem;
76     printf("input:");
77     while(scanf("%d", &elem) != EOF)
78     {
79         InQueue(&queue, elem);
80     }
81     PrintQueue(queue);
82     OutQueue(&queue);
83     PrintQueue(queue);
84     EmptyQueue(queue);
85     return OK;
86 }