The flags for the numeric base also affect input. If one of the flags for the numeric base is set,
all numbers are read using this base. If no flag for the base is set when numbers are read, the base
is determined by the leading characters: A number starting with 0x or 0X is read as a hexadecimal
number. A number starting with 0 is read as an octal number. In all other cases, the number is read
as a decimal value.