sscanf uses the brackets to format string

sscanf 函数使用中括号格式化字符串

在[]之中的字符串集合可以更好的格式化字符串 a set of characters in brackets ([ ]) can be substituted for the s (string) type character. The set of characters in brackets is referred to as a control string.

• [^characters] 匹配直到所有非此集合中的字符，直到此集合的字符出现为止。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.

• [characters] 匹配直到出现未在此集合中出现的字符input field is read up to the first character that does not appear in the control string

int
main(int argc, char * * a rgv)
{
    char* s = "key= value ";
    char key[1024] = {0};
    char value[1024] = {0};
    char* digits = "pi3.1415926";
    sscanf(s, "%[^=]=%[^\0]", key, value);
    printf("%s\n%s\n", key, value);
    sscanf(digits, "%[abcdefghijklmnopqrstuvwxyz]%[1234567890.]", key, value);
    printf("%s\n%s\n", key, value);
    return 0;
}