So, when you want to figure out the address & of a variable, you say ampersand.

当你想得到一个变量的地址,你可以指明。

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Well, get string again is returning the address of the string the user typed in, D the address of the very first character like the letter D and storing that address in this variable s1.

好的，GetString返回的是,用户输入的字符串的地址，第一个字符的地址，比如字母,然后把这个地址存储在这个变量s1中。

哈佛公开课 - 计算机科学课程节选