1 #include<stdio.h>
2 #include<stdlib.h>
3 #define MAXNODE 100
4 typedef int status;
5 #define MAX 100
6
7 typedef struct Bitree
8 {
9 struct Bitree *lchild;
10 struct Bitree *rchild;
11 char data;
12 }BiTree ,*BiTnode;
13
14 BiTree *Create( )//建立二叉树
15 {
16 int i,j;
17 BiTree *root,*s,*Q[MAX];
18 char ch;
19 printf("请输入要建立的树的下标和数值:");
20 // getchar( );
21 scanf("%d %c",&i,&ch);
22 while(i!=0&&ch!='0')
23 {
24 s=(BiTree *)malloc(sizeof(BiTree));
25 s->data=ch;printf("%d%c*",i,ch);
26 s->lchild=NULL;
27 s->rchild=NULL;
28 Q[i]=s;
29 if(i==1)
30 root=s;
31 else
32 {
33 j=i/2;
34 if(i%2==0)
35 Q[j]->lchild=s;
36 else
37 Q[j]->rchild=s;
38 }
39 scanf("%d %c",&i,&ch);
40 }
41 return root;
42 }
43
44 int NRPreOrder(BiTnode bt)
45 {
46 BiTnode stack[MAXNODE],p;
47 int top; //
48 if(bt==NULL)
49 return 1;
50 top=-1;
51 p=bt;
52
53 while(!(p==NULL&&top==-1)){
54 while(p!=NULL){//printf("*");
55 printf("%c ",p->data);
56 if(top<MAXNODE-1){
57 top++;
58 stack[top]=p;
59 }
60 else{
61 printf("wrong\n");
62 return 0;
63 }
64 p=p->lchild;
65 }
66 if(top==-1)
67 return 1;
68 else{
69 p=stack[top];
70 top--;
71 p=p->rchild;
72 }
73 }
74 }
75
76
77 int main( )
78 {
79 BiTnode Bt;
80 Bt=Create( );
81 printf("\n");
82 NRPreOrder(Bt);
83 return 0;
84 }
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