3 So here what I'm doing is 17 divided by 13, but because of this parenthetical, , -- because of that parenthetical -- that has nothing to do with math; -- this is a programming language thing -- that is a casting operation.

所以这里我要做的是用17除以，但因为这样的题外话，因为那样的题外话-,还是没有做完这个数学题;,这是一个编程语言的东西-,那是一个计算操作。

哈佛公开课 - 计算机科学课程节选