C++ standard, §2.14.3/1 - Character literals
(...) An ordinary character literal that contains more than one c-char is a multicharacter literal . A multicharacter literal has type int and implementation-defined value.
普通的字符包含多个字符就是多字符,一个多字符是一个int类型。
根据上面的输出
61 -> 'a'
62 -> 'b'
63 -> 'c'