数据结构——栈的基本操作

/*

对栈实现初始化，插入栈顶元素，删除栈顶元素，遍历栈，清空栈等基本操作

*/

1 #include <stdio.h>
2 #include <malloc.h>
3 #include <stdlib.h>
4
5 #define true 1
6 #define false 0
7
8
9 typedef struct Node
10 {
11     int data;
12     struct Node *pNext;
13 }NODE, *PNODE;
14
15 typedef struct Stack
16 {
17     PNODE pTop;
18     PNODE pBottom;
19 }STACK, *PSTACK;
20
21 void init(PSTACK pS);
22 void push(PSTACK pS, int val);
23 void traverse(PSTACK pS);
24 int pop(PSTACK pS , int *val);
25 void clear(PSTACK pS);
26 int empty(PSTACK pS);
27
28 int main(void)
29 {
30     STACK S ;
31     int val;
32     int i;
33
34     init(&S);
35
36     push(&S,1);
37     push(&S,2);
38     push(&S,3);
39     push(&S,4);
40     push(&S,5);
41     push(&S,6);
42
43     traverse(&S);
44
45     if(pop(&S ,&val))
46     {
47         printf("遍历成功，出栈元素为%d\n",val);
48     }
49     else
50     {
51         printf("出栈失败！\n");
52     }
53     traverse(&S);
54
55     clear(&S);
56
57     traverse(&S);
58
59     return 0 ;
60 }
61
62 //栈的初始化
63 void init(PSTACK pS)
64 {
65     pS -> pTop = (PNODE)malloc(sizeof(NODE));
66
67     if(NULL == pS -> pTop)
68     {
69         printf("动态内存分配失败！");
70         exit(-1);
71     }
72     else
73     {
74         pS -> pBottom = pS -> pTop;
75         pS -> pTop -> pNext = NULL;
76     }
77
78     return ;
79 }
80
81 //插入元素到栈顶
82 void push(PSTACK pS , int val)
83 {
84     PNODE pNew = (PNODE)malloc(sizeof(NODE));
85
86     pNew -> data = val;
87     pNew -> pNext = pS -> pTop;
88     pS -> pTop = pNew;
89
90     return ;
91 }
92
93 //遍历栈S
94 void traverse(PSTACK pS)
95 {
96     PNODE p = pS -> pTop;
97
98     printf("栈内元素为：");
99     while(p != pS -> pBottom)
100     {
101         printf("%d\t", p -> data);
102         p = p -> pNext;
103     }
104
105     printf("\n");
106     return ;
107 }
108
109 //判断栈是否为空
110 int empty(PSTACK pS)
111 {
112     if(pS -> pTop == pS -> pBottom)
113     {
114         return true;
115     }
116     else
117         return false;
118 }
119
120 //删除栈顶元素并将其值赋给*val
121 int pop(PSTACK pS , int *val)
122 {
123     if(empty(pS))
124     {
125         return false;
126     }
127     else
128     {
129         PNODE r = pS -> pTop;
130         *val = r -> data;
131         pS -> pTop = r -> pNext;
132         free(r);
133         r = NULL;
134     }
135 }
136
137 //清空栈S
138 void clear(PSTACK pS)
139 {
140     if(empty(pS))
141     {
142         return;
143     }
144     else
145     {
146         PNODE p = pS -> pTop;
147         PNODE q = NULL;
148
149         while(p != pS -> pBottom)
150         {
151             q = p -> pNext;
152             free(p);
153             p = q ;
154         }
155
156         pS -> pTop = pS -> pBottom;
157
158         return;
159     }
160 }