左孩子右兄弟表示多叉树查找返回下一个节点

struct node{  
    node *parent;  
    node *next;  
    node *child;  
};  
  
node* next(node *node){  
    if(node == null)  
        return null;  
    if(node->child != null)  
        return node->child;  
    if(node->next != null)  
        return node->next; 
    while(node->parent->next == NULL && node->parent != root)  
        node = node->parent;  
    return node->parent->next; 
}