!!!!\u0021\u0021 (C99)\U000021\U000021 (C99)\x21\x21 (encoding-dependent)\041\041 (encoding-dependent)\u{21}\u{21} (C++23)\x{21}\x{21} (C++23, encoding-dependent)\o{041}\o{041} (C++23, encoding-dependent)\U00000021\U00000021\u0021\u0021\x21\x21 (encoding-dependent)\041\041 (encoding-dependent)\u0021\u0021\u{21}\u{21}\u0021\u0021\x21\x21\21\21\000021\000021=21=21%21%21