c - 请解释书中的这一行 'The C Programming Language' Pg 192

Question

"If the input stream has been separated into tokens up to a given character, the next token is the longest string of characters that could constitute a token."

这是我对此的解释:

假设我输入一个字符串 "abc xyz" ，那么这个输入中会有两个标记，"abc" 和 "xyz",所以"abc"与"xyz"之间用空格分隔，"xyz"是可以构成的最长字符串一个 token 。

我想知道我的理解是否正确？

Answer 1

是的，你基本上是对的，但上下文不同。具体来说，这与“输入”无关。

您所引用的章节描述了预处理阶段的“词法约定”和源文件的标记。

只是为了澄清，引用“词汇约定”中“标记”一章中的相关部分

Blanks, horizontal and vertical tabs, newlines, formfeeds and comments as described below (collectively, ``white space'') are ignored except as they separate tokens. Some white space is required to separate otherwise adjacent identifiers, keywords, and constants.

If the input stream has been separated into tokens up to a given character, the next token is the longest string of characters that could constitute a token.

因此，它不仅仅是“空格”字符，标记可以由任何空白元素分隔，如上所述。在本例中，是的，它是“空格”() 字符。