# Leetcode 405 - Convert a number into Hex

`Note:`

`Negative`

and`positive`

numbers are all store as`binary`

, so we don’t really need to worry about it.- Use
`bitmask 0xf`

to get the last 4 bits. - Use a string ‘0123456789abcdef’ and a num’s
`Mod with 16`

to get the char we want. (That’s smart!)

`Question:`

Given an integer `num`

, return a string representing its hexadecimal representation. For negative integers, `two’s complement`

method is used.

All the letters in the answer string should be lowercase characters, and there should not be any leading zeros in the answer except for the zero itself.

`Note`

: You are not allowed to use any built-in library method to directly solve this problem.

`Example:`

1 | Input: num = -1 |

`Code:`

1 | /** |