linux sscanf 空格,sscanf 特殊分隔符(逗号)

最新推荐文章于 2024-01-04 08:45:21 发布

转载最新推荐文章于 2024-01-04 08:45:21 发布 · 887 阅读

2 ·

CC 4.0 BY-SA版权

原文链接：http://t.csdn.cn/ZyuH3

文章标签：

#java #服务器 #前端

文章讨论了sscanf函数在处理逗号分隔的字符串时可能出现的问题，并提供了解决方案。使用%[^,]格式化说明符可以正确读取非逗号字符直到遇到下一个逗号。此方法遵循C语言标准，适用于解析非空格分隔的字符串。

一、sscanf在直接处理逗号分隔符的时候，会发生错误。

程序如下：

char *s = "aaa,bbb,ccc,ddd";

char a[32],b[32],c[32],d[32];

sscanf(s, "%s,%s,%s,%s\n", a, b, c, d);

printf("[%s][%s][%s][%s]\n", a, b, c, d);

结果为:

develop:/home/leon/test # ./a.out

[aaa,bbb,ccc,ddd][][][]

二、解决。将sscanf内的格式化输出改为以下形式:

sscanf(s, "%[^,],%[^,],%[^,],%s", a, b, c, d);

结果为:

develop:/home/leon/test # ./a.out

[aaa][bbb][ccc][ddd]

三、以下为MDSN的说明:

To read strings not delimited by space characters, a set of characters in brackets ([ ]) can be substituted for the s (string) type character. The corresponding input field is read up to the first character that does not appear in the bracketed character set. If the first character in the set is a caret (^), the effect is reversed: The input field is read up to the first character that does appear in the rest of the character set.

Note that %[a-z] and %[z-a] are interpreted as equivalent to %[abcde...z]. This is a common scanf function extension, but note that the ANSI standard does not require it.

理解:

%[] 指定字符集，即加了字符规则的'%s

^ 取反

%[^,] 取非','的内容,直到遇到','