二叉树的遍历及求其深度

#include <stdio.h>
#include <stdlib.h>
typedef struct btnode
{
    int data;
    struct btnode *lchild,*rchild;
}btnode,*btree;
//建立二叉树
btree createtree()
{
    btree T;
    char p;
    p=getchar();
    if (p=='#')
    T=NULL;
    else
    {
        T=(btree)malloc(sizeof(btnode));
        T->data=p;
        T->lchild=createtree();
        T->rchild=createtree();
    }
    return T;
}
//按先序遍历
void preorder(btree root)
{
    if (root!=NULL)
    {
        printf("%c",root->data);
        preorder(root->lchild);
        preorder(root->rchild);
    }
}
void inorder(btree root)
{
     if (root!=NULL)
    {
        inorder(root->lchild);
        printf("%c",root->data);
        inorder(root->rchild);
    }
}
void postorder(btree root)
{
    if (root!=NULL)
    {
        postorder(root->lchild);
        postorder(root->rchild);
        printf ("%c",root->data);
    }
}
int depth(btree t)
{
    if (t==NULL)
    return 0;
    else
    {
        int h1,h2,h;
        h1=depth(t->lchild);
        h2=depth(t->rchild);
        if (h1>h2)
        h=h1+1;
        else
        h=h2+1;
        return h;
    }
}
int main()
{
   btree t;
   t=createtree();
   printf("输入二叉树的先序排列(空的地方输入#)：");
   printf("按先序遍历二叉树\n");
   preorder(t);
   printf ("\n");
   printf("按中序遍历二叉树\n");
   inorder(t);
   printf ("\n");
   printf("按后序遍历二叉树\n");
   postorder(t);
   printf ("\n");
   printf ("树的深度\n");
   printf ("%d\n",depth(t));

    return 0;
}