No, it doesn't. hex interprets its argument as being a hex number. But what was asked was to get a hex representation of a number.

BTW, your $dec_num is misleading. hex just returns a number. It doesn't make much sense calling that a decimal number. "decimal" is relevant when we talk about representing numbers - for instance when reading in a number, or printing it. But all we do here is storing it. Most likely in a binary format - but which format it is, is irrelevant on the level of the language.

-- Abigail