\t
\s
\w
\t matches a single tab character.
Example: \tint abc; matches a tab character followed by int abc;.
\s matches a single space character.
Example: \sif matches a space character followed by if.
\w matches a single white space character. In other words, \w matches either a tab or space character.
Example: \wwhile matches either a tab or space character, followed by while.