数据结构(8) - 链式队列
作者：互联网
链式队列，使用链表实现的队列存储结构，链式队列的实现思想同顺序队列类似，只需创建两个指针（命名为 top 和 rear）分别指向链表中队列的队头元素和队尾元素。
linked-queue.c
1 /**
2 * C data structure linked queue example.
3 *
4 * License - MIT.
5 */
6
7 #include "linked-queue.h"
8
9
10 /**
11 * linkqueue_isempty - Determine if the queue is empty.
12 */
13 bool linkqueue_isempty(LPQUEUECURSOR lpcursor)
14 {
15 return (lpcursor->front == lpcursor->rear);
16 }
17
18
19 /**
20 * linkqueue_put - Put data to queue.
21 */
22 int linkqueue_put(LPQUEUECURSOR lpcursor, int data)
23 {
24 LPLINKQUEUE node = NULL;
25
26 node = (LPLINKQUEUE) malloc(sizeof(LINKQUEUE));
27
28 if (NULL == node) {
29 printf("Error in queue put.\n");
30 return -1;
31 }
32
33 /* Put data to queue. */
34 node->data = data;
35 node->next = lpcursor->rear->next;
36 lpcursor->rear->next = node;
37 lpcursor->rear = lpcursor->rear->next;
38
39 return 0;
40 }
41
42
43 /**
44 * linkqueue_get - Get data from queue.
45 */
46 int linkqueue_get(LPQUEUECURSOR lpcursor, int *data)
47 {
48 LPLINKQUEUE tmp;
49
50 /* Determine if queue is empty. */
51 if (linkqueue_isempty(lpcursor))
52 return -1;
53
54 /* Get data from queue. */
55 tmp = lpcursor->front;
56 lpcursor->front = lpcursor->front->next;
57 *data = lpcursor->front->data;
58
59 free(tmp);
60
61 return 0;
62 }
63
64
65 /**
66 * linkqueue_init - Initialize linked queue.
67 */
68 int linkqueue_init(LPQUEUECURSOR *lpcursor)
69 {
70 /* Allocate cursor memory space. */
71 *lpcursor = (LPQUEUECURSOR) malloc(sizeof(QUEUECURSOR));
72
73 if (NULL == *lpcursor) {
74 printf("Error in queue init.\n");
75 return -1;
76 }
77
78 /* Allocate head node memory space. */
79 (*lpcursor)->front = (LPLINKQUEUE) malloc(sizeof(LINKQUEUE));
80
81 if (NULL == (*lpcursor)->front) {
82 printf("Error in queue init.\n");
83 return -1;
84 }
85
86 (*lpcursor)->front->next = NULL;
87 (*lpcursor)->rear = (*lpcursor)->front;
88
89 return 0;
90 }
91
92
93 /**
94 * linkqueue_clear - Clear linked queue.
95 */
96 int linkqueue_clear(LPQUEUECURSOR lpcursor)
97 {
98 int tmp = -1;
99
100 while (!linkqueue_isempty(lpcursor))
101 {
102 linkqueue_get(lpcursor, &tmp);
103 }
104
105 free(lpcursor);
106 lpcursor = NULL;
107
108 return 0;
109 }
linked-queue.h
1 /**
2 * C data structure linked queue example.
3 *
4 * License - MIT.
5 */
6
7 #ifndef __LINKED_QUEUE_H__
8 #define __LINKED_QUEUE_H__
9
10
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <stdbool.h>
14
15
16 typedef struct _LINKQUEUE {
17 int data;
18 struct _LINKQUEUE *next;
19 } LINKQUEUE, *LPLINKQUEUE;
20
21 typedef struct _QUEUECURSOR {
22 LPLINKQUEUE front, rear;
23 } QUEUECURSOR, *LPQUEUECURSOR;
24
25
26 bool linkqueue_isempty (LPQUEUECURSOR lpcursor);
27 int linkqueue_put (LPQUEUECURSOR lpcursor, int data);
28 int linkqueue_get (LPQUEUECURSOR lpcursor, int *data);
29 int linkqueue_init (LPQUEUECURSOR *lpcursor);
30 int linkqueue_clear (LPQUEUECURSOR lpcursor);
31
32
33 #endif /* __LINKED_QUEUE_H__ */
mian.c
1 /**
2 * C data structure linked queue example.
3 *
4 * License - MIT.
5 */
6
7 #include <stdio.h>
8
9 #include "linked-queue.h"
10
11
12 /**
13 * queue_test - Test linked queue example.
14 */
15 int queue_test(LPQUEUECURSOR lpcursor, int buf[], int len)
16 {
17 int i = 0;
18 int data = 0;
19
20 printf("Put data: ");
21
22 for (i = 0; i < len; i++) {
23 linkqueue_put(lpcursor, buf[i]);
24 printf("%d ", buf[i]);
25 }
26
27 printf("\nGet data: ");
28
29 for (i = 0; i < len; i++) {
30 linkqueue_get(lpcursor, &data);
31 printf("%d ", data);
32 }
33
34 printf("\n");
35
36 return 0;
37 }
38
39
40 /**
41 * Main function.
42 */
43 int main(void)
44 {
45 int buf[5] = {1, 2, 3, 4, 5};
46 LPQUEUECURSOR lpcursor = NULL;
47
48 linkqueue_init(&lpcursor);
49
50 queue_test(lpcursor, buf, 5);
51
52 linkqueue_clear(lpcursor);
53
54 return 0;
55 }
Makefile
1 # Makefile 2 CC = gcc 3 CFLAGS = -Wall -g -O0 4 5 SRC = main.c linked-queue.c 6 7 OBJ = linkqueue-test 8 9 $(OBJ) : $(SRC) 10 $(CC) $(CFLAGS) -o $@ $^ 11 12 clean: 13 $(RM) $(OBJ) *.o *.*.sw?
详细代码请参考Github: [Link] [https://github.com/Phoebus-Ma/C-Helper/tree/main/Class-1/Queue.C].
标签：lpcursor,LPQUEUECURSOR,队列,linkqueue,queue,int,链式,数据结构,data 来源： https://www.cnblogs.com/tinyshark/p/16411788.html