Just to drive home one more reason why I don't want to have changes to the values other than through pre-defined things.

注意如果我这么做的话会发生什么,我可以说我想要改变,某个特定点的半径。

麻省理工公开课 - 计算机科学及编程导论课程节选

A good, hygienic way of doing this is, not only do I not go in and change things except through a pre-defined method, I shouldn't read it other Cartesian than through a pre-defined method.

做这个的方式是，我不仅仅要通过提前定义好的方法,来改变数值,我还应该通过提前定义好的方法，来读这个值,我应该用。

麻省理工公开课 - 计算机科学及编程导论课程节选