创建一个由10个节点组成的二叉树结构，并按前根、中根、后根对该二叉树进行遍历，并输出遍历结果(c语言)

#include
struct Bitree
{
   char c;
   struct Bitree *l;
   struct Bitree *r;
};
struct Bitree * create(){
    char ch;
    struct Bitree *s;
    scanf("%c",&ch);
    if(ch=='#')
        return NULL;
    else
       {
            s=(struct Bitree *)malloc(sizeof(struct Bitree));
            s->c=ch;
            s->l=create();
            s->r=create();
            return s;
                                                                   
    }
}
void preorder(struct Bitree *root)
{
  if(root!=NULL)
  {
     printf("%c",root->c);
     preorder(root->l);
     preorder(root->r);
  }
}
void inorder(struct Bitree *root)
{
  if(root!=NULL)
  {
     inorder(root->l);
     printf("%c",root->c);
     inorder(root->r);
  }
}
void lastorder(struct Bitree *root)
{
  if(root!=NULL)
  {
     lastorder(root->l);
     lastorder(root->r);
     printf("%c",root->c);
  }
}

遍历不会还是整个都不会？