二叉树

typedef struct node{
int data;
struct node *lchild,*rchild;
}bitree;

void swapbitree(bitree *bt)
{
bitree *p;
if(bt == NULL)
return;
swapbitree(bt->lchild);//交换根结点左子树上的结点的左右孩子结点
swapbitree(bt->rchild);
p = bt->lchild;//最后交换根结点的左右孩子结点
bt->lchild = bt->rchild;
bt->rchild = p;
}