构建二叉树（数据结构，李春葆）

#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
typedef struct node
{
	char data;
	struct node* lchild;
	struct node* rchild;
}BTNode;
void GreatBTree(BTNode *&b,char *str);
void DispBTree(BTNode *b);
void DestroyBTree(BTNode * &b);
BTNode *FindNode(BTNode *b,char x);
BTNode *LchildNode(BTNode *p);
int BTHeight(BTNode *b);
int main()
{
	BTNode *b,*p; 
	char str[100],x='B';
	scanf("%s",str);
	GreatBTree(b,str);
	DispBTree(b);
	p=FindNode(b,x);
	printf("%c\n",p->data);
	p=LchildNode(b);
	printf("%c\n",p->data);
	//int a;
	printf("%d\n",BTHeight(b));
	return 0;
}

void GreatBTree(BTNode *&b,char *str)
{
	BTNode *St[100],*p;
	int top=-1,k,j=0;
	char ch;
	b=NULL;
	ch=str[j];
	while(ch!='\0')
	{
		switch(ch)
		{
			case '(':top++;St[top]=p;k=1;break;
			case ')':top--;break;
			case ',':k=2;break;
		    default :
		    	p=(BTNode *)malloc(sizeof(BTNode));
		    	p->data=ch;
		    	p->lchild=p->rchild=NULL;
		    	if(b==NULL)
		    	b=p;
		    	else
		    	{
		    		switch(k)
		    		{
		    			case 1 :St[top]->lchild=p;break;
		    			case 2 :St[top]->rchild=p;break;
					}
				}
		}
		j++;
		ch=str[j];
	}	
}


void DispBTree(BTNode *b)
{
	if(b!=NULL)
	{
		printf("%c",b->data);
		if(b->lchild!=NULL||b->rchild!=NULL) 
		{
			printf("(");
			DispBTree(b->lchild);
			if(b->rchild!=NULL)
			printf(",");
			DispBTree(b->rchild);
			printf(")");
		}
	}
	
}

void DestroyBTree(BTNode* &b)
{
	if(b!=NULL)
	{
		DestroyBTree(b->lchild);
		DestroyBTree(b->rchild);
		free(b);
	}
}

BTNode *FindNode(BTNode *b,char x)
{
	BTNode *p;
	if(b==NULL)
	return NULL;
	else if(b->data==x)
	return b;
	else
	{
		p=FindNode(b->lchild,x);
		if(p!=NULL)
		return p;
		else
		return FindNode(b->rchild,x); 
	}
}


BTNode *LchildNode(BTNode *p)
{
	return p->lchild;
 } 

int BTHeight(BTNode *b)
{
	int lchild,rchild;
	if(b==NULL) return 0;
	else
	{
		lchild=BTHeight(b->lchild);
		rchild=BTHeight(b->rchild);
		return (lchild>rchild)?(lchild+1):(rchild+1); //不能用lchild++
	}
}