This was the special value that said to the computer string stops here and because you have that barrier given to you at the end of every string, just the most efficient way you can pass strings around is just by passing the address of their very first bytes, the location in RAM.

这是一个特殊的值，表示的是,字符串在这里结束，因为在每个字符串的末尾,都有那个关卡，这是一个最有效率的方式，你可以通过传递,字符串的第一个字节的地址来传递一个字符串，地址是在RAM中的。

计算机科学课程节选 : 哈佛公开课