链表头插法
head_handle = null;
int button_start(struct Button* A)
{
struct Button* target = head_handle;
while(target) {//这个循环用来判断是不是重复的节点
if(target == A) return -1; //already exist.
target = target->next;
}
A->next = head_handle;//核心内容就是这句和下句
head_handle = A;
return 0;
}
button_start(A);
button_start(B);
button_start(C);