c语言之 *指针与 **指针

*n 一级指针：

&n	n	*n
自身地址	指向地址	指向地址值

**s 二级指针：

&s	s	*s	**s
自身地址	一级指针地址	一级指针指向地址	一级指针指向地址值

CHILD *walk, *next, *tmp_child, **scan;next = walk->next
scan = &walk->next;
while (*scan) {     // *scan = walk->nextif (!tree_equal(walk->child, (*scan)->child)) {     // (*scan)->child) = walk->next->childscan = &(*scan)->next;                          // &(*scan)->next = &walk->next->child} else {if (next == *scan)                              // (next == *scan) ==> (next == walk->next)next = (*scan)->next;                       // (*scan)->next = walk->next->nextcount++;tmp_child = (*scan)->next;                      // (*scan)->next = walk->next->nextfree(*scan);*scan = tmp_child;                              // *scan = walk->next}
}