So what that means is the compiler is actually going to first "cast" so to speak 13 from whatever it is - to a float -- to a floating point value -- and then perform the division for us.

所以这里的意思是编译器将,做“计算“，譬如13这样一个浮点数,-到另一个浮点数-,然后为我们处理除法。

哈佛公开课 - 计算机科学课程节选