The only thing that you have to put in the function prototype, ; again, is three things; one, the name of the function; the return value; and its arguments.

你唯一要加入到函数原型中的东西，是有三个东西，一，函数的名字;,返回值，和它的参数。

哈佛公开课 - 计算机科学课程节选