关于类私有变量的访问 试验。同一个类中两个变量A和B，可以互相访问对方的私有变量。例如：两个人Jim 和Peter，都有私有“钱”，那么Jim可以偷Peter的私人钱。-Category of private variables about the pilot visit. With a category two variables A and B, can visit each other each other' s private variables. For example: two people Jim and Peter, have a private " money" , then Jim can steal Peter' s private money. ? ? ! !