1 #include <stdio.h>
2 #include <string.h>
3 #include <stdlib.h>
4 #define N 100
5
6 typedef char datatype;
7 void visit(datatype data);
8
9 typedef struct bnode
10 {
11 datatype data;
12 struct bnode *lchild, *rchild;
13 } BTNode, *BTree, **B_BTree;
14
15 typedef struct stack
16 {
17 BTree node[N];
18 //int tag[N];
19 int top;
20 } Stack;
21
22 void push(Stack *s, BTree T)
23 {
24 s->node[++s->top] = T;
25 }
26
27 BTree get_top(Stack *s)
28 {
29 return s->node[s->top];
30 }
31
32 BTree pop(Stack *s)
33 {
34 if(s->top != -1)
35 {
36 s->top--;
37 return s->node[s->top + 1];
38 }
39 else
40 {
41 return NULL;
42 }
43 }
44
45 void visit(datatype data)
46 {
47 printf("%c", data);
48 }
49
50 void preorder(BTree T)
51 {
52 if(T)
53 {
54 visit(T->data);
55 preorder(T->lchild);
56 preorder(T->rchild);
57 }
58 }
59
60 void inorder(BTree T)
61 {
62 if(T)
63 {
64 inorder(T->lchild);
65 visit(T->data);
66 inorder(T->rchild);
67 }
68 }
69
70 void postorder(BTree T)
71 {
72 if(T)
73 {
74 postorder(T->lchild);
75 postorder(T->rchild);
76 visit(T->data);
77 }
78 }
79
80 void cur_preorder(BTree t)
81 {
82 Stack s;
83 BTree temp = t;
84 s.top = -1;
85 while(temp || s.top != -1)
86 {
87 while(temp)
88 {
89 visit(temp->data);
90 push(&s, temp);
91 temp = temp->lchild;
92 }
93 if(s.top > -1)
94 {
95 temp = pop(&s);
96 temp = temp->rchild;
97 }
98 }
99 }
100
101 void cur_inorder(BTree t)
102 {
103 Stack s;
104 BTree temp = t;
105 s.top = -1;
106 while(temp || s.top != -1)
107 {
108 while(temp)
109 {
110 push(&s, temp);
111 temp = temp->lchild;
112 }
113 if(s.top > -1)
114 {
115 temp = pop(&s);
116 visit(temp->data);
117 temp = temp->rchild;
118 }
119 }
120 }
121
122 void cur_postorder(BTree t)
123 {
124 Stack s;
125 BTree temp, pre = NULL;
126 temp = t;
127 s.top = -1;
128 while(temp || s.top != -1)
129 {
130 while(temp)
131 {
132 push(&s, temp);
133 temp = temp->lchild;
134 }
135 temp = get_top(&s);
136 if(temp->rchild == NULL
137 || temp->rchild == pre)
138 {
139 visit(temp->data);
140 pre = temp;
141 temp = NULL;
142 pop(&s);
143 }
144 else
145 {
146 temp = temp->rchild;
147 }
148 }
149 }
150
151 /*层次遍历*/
152 typedef struct
153 {
154 BTree node[N];
155 int front;
156 int rear;
157 } queue;
158
159 void init_queue(queue *Q)
160 {
161 Q->front = Q->rear = 0;
162 }
163
164 void en_queue(queue *Q, BTree e)
165 {
166 Q->node[Q->rear] = e;
167 Q->rear = (Q->rear + 1) % N;
168 }
169
170 void de_queue(queue *Q, B_BTree e)
171 {
172 *e = Q->node[Q->front];
173 Q->front = (Q->front + 1) % N;
174 }
175
176 int is_empty(queue *Q)
177 {
178 return Q->rear == Q->front;
179 }
180
181 void level_order(BTree t)
182 {
183 queue Q;
184 init_queue(&Q);
185 BTree p = t;
186 if(p)
187 {
188 en_queue(&Q, p);
189 while(!is_empty(&Q))
190 {
191 de_queue(&Q, &p);
192 visit(p->data);
193 if(p->lchild)
194 {
195 en_queue(&Q, p->lchild);
196 }
197 if(p->rchild)
198 {
199 en_queue(&Q, p->rchild);
200 }
201 }
202 }
203 }
204
205 void create_tree(B_BTree T)
206 {
207 char temp;
208 temp = getchar();
209 if(temp == ' ')
210 {
211 *T = NULL;
212 }
213 else
214 {
215 (*T) = (BTNode *)malloc(sizeof(BTNode));
216 (*T)->data = temp;
217 create_tree(&(*T)->lchild);
218 create_tree(&(*T)->rchild);
219 }
220 }
221
222 int main()
223 {
224 BTree T;
225 printf("请按次数顺序输入字符：\n");
226 create_tree(&T);
227 preorder(T);
228 printf("\n");
229 cur_preorder(T);
230 printf("\n");
231 inorder(T);
232 printf("\n");
233 cur_inorder(T);
234 printf("\n");
235 postorder(T);
236 printf("\n");
237 cur_postorder(T);
238 printf("\n");
239 level_order(T);
240 printf("\n");
241 return 0;
242 }
