scanf()小技巧，使用%[]进行字符串解析

//=========Sample 1==========
char line[256];
char * name;

fgets(line, 256, stdin);
const char * p = strchr(line, ',');
name = new char[p - line + 1];
strncpy(name, line, p - line);
name[p-line] = '\x00';
sscanf(p+1, "%d,%d,%d,%d,%d,%d", &age, &id, \
&grades[0], &grades[1], &grades[2], &grades[3]);

delete []name;
//=========Sample 2===========
char name[32];

scanf("%[^,],%d,%d,%d,%d,%d,%d", name, &age, &id, \
&grades[0], &grades[1], &grades[2], &grades[3]);

//====================
input：
Tom,18,7817,80,80,90,70
//====================
上面的例子需要解析一行输入，里面的数据项用”,”分割，平常的“%s”是不能识别逗号分隔的，只能识别空白字符，例如空格、制表符、回车。
这里使用“%[]”来匹配，“%[^,]”的意思是匹配到“,”为止，包含“,”，“%[^,],”的意思是匹配到“,”为止，不包含“,”。

附（man scanf）节选 ：

SCANF(3)                  Linux Programmer's Manual                 SCANF(3)
...

Conversions
The following type modifier characters can appear in a conversion
specification:

[      Matches a nonempty sequence of characters from the specified
set of accepted characters; the next pointer must be a pointer
to char, and there must be enough room for all the characters
in the string, plus a terminating null byte.  The usual skip
of leading white space is suppressed.  The string is to be
made up of characters in (or not in) a particular set; the set
is defined by the characters between the open bracket [
character and a close bracket ] character.  The set excludes
those characters if the first character after the open bracket
is a circumflex (^).  To include a close bracket in the set,
make it the first character after the open bracket or the
circumflex; any other position will end the set.  The hyphen
character - is also special; when placed between two other
characters, it adds all intervening characters to the set.  To
include a hyphen, make it the last character before the final
close bracket.  For instance, [^]0-9-] means the set
"everything except close bracket, zero through nine, and
hyphen".  The string ends with the appearance of a character
not in the (or, with a circumflex, in) set or when the field
width runs out.