20.链式队列

运行截图:
完整代码:
 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 
 4 #define datatype int
 5 
 6 typedef struct queue
 7 {
 8     datatype data;
 9     struct queue *pNext;
10 }Queue,*PQueue;
11 
12 //入队 从尾部入,从头部出
13 PQueue enq(PQueue phead, datatype data)
14 {
15     PQueue pnew = (PQueue)malloc(sizeof(Queue));
16     pnew->data = data;
17     pnew->pNext = NULL;
18     if (phead == NULL)
19     {
20         phead = pnew;//直接插入
21     }
22     else
23     {
24         PQueue ptemp = phead;
25         //循环到尾部
26         while (ptemp->pNext != NULL)
27         {
28             ptemp = ptemp->pNext;
29         }
30         ptemp->pNext = pnew;//尾部插入
31     }
32     return phead;
33 }
34 
35 //出队
36 PQueue deq(PQueue phead, datatype *pdata)
37 {
38     if (phead == NULL)
39     {
40         return NULL;
41     }
42     else
43     {
44         *pdata = phead->data;//获取弹出的数据
45         PQueue ptemp = phead->pNext;
46         free(phead);
47         phead = ptemp;
48     }
49 }
50 
51 //显示
52 void show(PQueue phead)
53 {
54     if (phead == NULL)
55     {
56         return;
57     }
58     else
59     {
60         printf("%5d", phead->data);
61         show(phead->pNext);//递归调用
62     }
63 }
64 
65 void main()
66 {
67     Queue *phead = NULL;
68     for (int i = 0; i < 10; i++)
69     {
70         phead = enq(phead, i);
71         printf("
queue");
72         show(phead);
73     }
74 
75     while (phead != NULL)
76     {
77         datatype data;
78         phead = deq(phead, &data);
79         printf("
dequeue%d", data);
80         printf("
queue");
81         show(phead);
82     }
83 
84     system("pause");
85 }