So even though increment is obviously increment declared and defined in this function, it's later; so it's too late for me to use it in main.

很明显，即使在这个函数中,已经声明和定义;,也太迟了，以至于，我在main函数中不能使用它。

哈佛公开课 - 计算机科学课程节选

Well, simply with the * notation at least on the way in when you declare the function called swap, you simply say this is not going to take an int and another int because that's useless.

好的，简单说，当你声明一个函数调用swap函数时,使用*符号，你可以简单说，这不能使用一个int数和另外一个int数,因为那是无效的。

哈佛公开课 - 计算机科学课程节选