二叉树建立

Question

#include<iostream.h>
#include<stdio.h>
#include<stdlib.h>
#include<malloc.h>
typedef struct node
{
	int data;
	struct node * left,*right;
}btree;
btree * find(btree *p, int x)
{
	btree *q;
	if(p==NULL)
		return (NULL);
	else
		if(p->data==x)
			return p;
		else
		{
		    q=find(p->left,x);
		    if(p==NULL)
			{
			    q=find(p->right,x);
			    return q;
			}
            else
			 return q;
		}
}
btree *create()
{
	int pvalue,cvalue,type,i=1;
	btree *p,*q,*s,*head;
	cout<<"输入建立二叉树序列（以-1表示输入结束）"<<endl;
	cout<<"第"<<i++<<"个节点=>"<<endl<<"    根节点值：";
    cin>>cvalue;
	if(cvalue!=-1)
	{
		head=(btree *)malloc(sizeof(btree));
		head->data=cvalue;
		head->left=NULL;
		head->right=NULL;
	}
	else 
		return (NULL);
	do
	{
		cout<<"第"<<i++<<"个节点=>"<<endl<<"    父节点值：";
		cin>>pvalue;
		if(pvalue!=-1)
		{
			do
			{
				cout<<"　左（0）或右（1）节点";
				cin>>type;
			}while(type!=0&&type!=1);
			cout<<"    当前节点值：";
			cin>>cvalue;
		}
		if(cvalue!=-1)
		{
			p=head;
			q=find(p,pvalue);
			if(q!=NULL)
			{
				s=(btree *)malloc(sizeof(btree));
				s->data=cvalue;
				s->left=NULL;
				s->right=NULL;
				if(type==0) q->left=s;
				if(type==1) q->right=s;
			}
			else
			{
				cout<<"已建的二叉树中没有指定值的节点"<<endl;
				i--;
			}
		}
	}while(pvalue!=-1);
	return (head);
}
void main()
{
	btree *p;
	p=create();
	cout<<p<<endl;
}