树的结构

#include<stdio.h>
#include<stdlib.h>
struct node
{
 char  date;
 struct node *left,*right;
};
typedef struct node* tree;
int cretree(tree *h)
{
 char c;
 scanf("%c",&c);
 if(c==' ')  *h=NULL;
 else{
  *h=(node *)malloc(sizeof(node));
  (*h)->date=c;
  cretree(&((*h)->left));
  cretree(&((*h)->right));
 }
 return 1;
}
int visttree(tree h,int level)
{
 if(NULL!=h)
 {
  printf("%c %d\n",h->date,level);
  visttree(h->left,level+1);
  visttree(h->right,level+1);
 }
}
int main()
{
 tree h=NULL;
 int n=1;
 cretree(&h);
 visttree(h,n);
 getchar();
}