1 #include <stdio.h>
2 #include <stdlib.h>
3 #include <strings.h>
4 #define MAX 100
5
6 char * p;
7 typedef struct BTree{
8 char * str;
9 struct BTree * lchild;
10 struct BTree * rchild;
11 }BTree;
12
13 BTree* creat_tree(){
14 BTree* temp;
15 while(*p==' ')p++;
16 if(*p=='#'){
17 p++;
18 return NULL;
19 }
20 if(*p!=' '){
21 int i=0;
22 temp = (BTree *)malloc(sizeof(BTree));
23 temp->str[i++]=*p++;
24 temp->lchild=creat_tree();
25 temp->rchild=creat_tree();
26 }
27 return temp;
28 }
29
30 void pre_visit(BTree* node){
31 printf("%c",node->str);
32 if(node->lchild!=NULL)pre_visit(node->lchild);
33 if(node->rchild!=NULL)pre_visit(node->rchild);
34 }
35 int main()
36 {
37 char tree[MAX];p=tree;
38 BTree * head;
39 printf("Please input the tree(use char and #)\n要求按照先序遍历的方式输入，加上#进行区分\n例如123# #4##5##:\n");
40 //scanf("%s",tree);
41 gets(tree);
42
43 if(*p!='\0'&&*p!=' '&&*p!='#'){
44 head=(BTree *)malloc(sizeof(BTree));
45 int i=0;
46 head->str[i++]=*p++;
47 //printf("head is %c",head->str);
48 head->lchild=creat_tree();
49 head->rchild=creat_tree();
50 }
51
52 printf("tree is :\n");
53 pre_visit(head);
54 return 0;
55 }
