1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
/* Standard C */
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
/* Project */
#include "util.h"
typedef int T;
struct list_node {
struct list_node *next;
T data;
};
struct list {
struct list_node *head, *tail;
};
void
list_init(struct list *list)
{
list->head = NULL;
}
static struct list_node *
create_node(struct list_node *next, T data)
{
struct list_node *node = malloc(sizeof *node);
if ( node != NULL ) {
node->next = next;
node->data = data;
}
return node;
}
void
list_push_back(struct list *list, T data)
{
struct list_node *node = create_node(NULL, data);
if ( node != NULL ) {
if ( list->head == NULL ) {
list->head = node;
}
else {
list->tail->next = node;
}
list->tail = node;
}
else {
ERROR("out of memory");
}
}
void
list_push_front(struct list *list, T data)
{
struct list_node *node = create_node(list->head, data);
if ( node != NULL ) {
if ( list->head == NULL ) { // Einfügen in eine leere Liste?
list->tail = node;
}
list->head = node;
}
else {
ERROR("out of memory");
}
}
bool
list_pop_front(struct list *list, T *data)
{
if ( list->head != NULL ) {
struct list_node *next = list->head->next;
if ( data != NULL ) {
*data = list->head->data;
}
free(list->head);
list->head = next;
return true;
}
else {
return false;
}
}
bool
list_empty(struct list *list)
{
return list->head == NULL;
}
void
list_free(struct list *list)
{
struct list_node *item, *next;
for ( item = list->head; item; item = next ) {
next = item->next;
free(item);
}
}
int
main()
{
struct list list[1];
list_init(list);
for ( int i = 0; i != 10; ++i )
list_push_front(list, -i);
for ( int i = 0; i != 10; ++i )
list_push_back(list, i);
while ( !list_empty(list) ) {
int i;
if ( list_pop_front(list, &i) )
printf("%d\n", i);
else
ERROR("this shouldn't happen!");
}
list_free(list);
return EXIT_SUCCESS;
}
|
