指针趣味小题

这小段代码帮助理解下指针和对象的大小，& 和*的作用

#include <stdio.h>
#include<iostream>

#define TElemType int

//构造结点的结构体
typedef struct BiTNode 
{
    TElemType data;//数据域

    struct BiTNode *lchild, *rchild;//左右孩子指针

}BiTNode, *BiTree;

int main()
{
    std::cout << "sizeof(BiTNode)  = "<<sizeof(BiTNode) << std::endl;
    std::cout << "sizeof(BiTree)  = " << sizeof(BiTree) << std::endl;
    BiTree Tree;
    std::cout <<"#####################" << std::endl;
    std::cout << "sizeof(Tree)  = " << sizeof(Tree) << std::endl;
    std::cout << "sizeof(&Tree)  = " << sizeof(&Tree) << std::endl;
    std::cout << "sizeof(*Tree)  = " << sizeof(*Tree) << std::endl;
    
    std::cin.get();
    return 0;
}

答案是:

sizeof(BiTNode)  = 12
sizeof(BiTree)  = 4
#####################
sizeof(Tree)  = 4
sizeof(&Tree)  = 4
sizeof(*Tree)  = 12