It's in a file called swap.C. Everything should be alphabetical so it should be toward the end of this week's packet and notice that it's almost identical except for a couple of syntax changes.

在一个叫做swap。c的文件中，对于这周末的数据包来说,所有的东西都是字母,请注意,除了几个语法改变,它几乎是一样的。

哈佛公开课 - 计算机科学课程节选

A If you want to convert a number like 65 to the letter A, you just have tell the computer "cast that int to a char."

如果你要把一个像65这样的数字转换为字母，你只需要告诉计算机“把那个int型数据转换成char型处理“

哈佛公开课 - 计算机科学课程节选