Scanset in C

scanf family functions support scanset specifiers which are represented by %[]. Inside scanset, we can specify single character or range of characters. While processing scanset, scanf will process only those characters which are part of scanset. We can define scanset by putting characters inside squre brackets. Please note that the scansets are case-sensitive.

For Eg:

If we want to get only capital letters from stdin we can use the following:

scanf("%[A-Z]s", str);

If we want to get only small letters from stdin we can use the following:

scanf("%[a-z]s", str);

If first character of scanset is ‘^’, then the specifier will stop reading after first occurrence of that character. For example, given below scanset will read all characters but stops after first occurrence of ‘o’

scanf("%[^o]s", str);

If we want to read a line from stdin into the buffer pointed to by s until either a terminating newline or EOF found.

scanf("%[^\n]s", str);