Savnet CPP #3
===

# 1. IPv6

As a user,
I want to validate an IPv6 address,
So that I don't mess up my configuration.

> An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets, a group sometimes also called a hextet). The groups are separated by colons (:). An example of an IPv6 address is:
>
> `2001:0db8:85a3:0000:0000:8a2e:0370:7334`

([source](https://en.wikipedia.org/wiki/IPv6_address))

**Acceptance criteria:**
1. Get from standard input, one line of string: the IPv6 to validate.
2. Each group of 16 bits, must be present to consider it valid.
3. Leading zeros for each group are optional. e.g. `0370` or `370` are both considered valid.
4. Valid chars are `0-9` and `a-f` (the [hexadecimal chars](https://simple.wikipedia.org/wiki/Hexadecimal)) - case insensitive.

## Examples

Input:
`2001:0db8:85a3:0000:0000:8a2e:0370:7334`

Output:
`Valid`

--

Input:
`0001:08:A3:00:0:8a2e:0370:7334`

Output:
`Valid`

--

Input:
`08:A3:00:0:11:12:AAFF`

Output:
`Invalid! Not enough groups.`

--

Input:
`11:22:08:A3:00:0:11:12:AAFF`

Output:
`Invalid! Too many groups.`

--

Input:
`11XY:22:A3:00:0:11:12:AAFF`

Output:
`Invalid! Unexpected hex char.`

# 2. Palindrome

As a user,
I want to enter a positive two-byte decimal number,
So that I find out if its binary representation is a palindrome or not.
>
> [Palindrome numbers](https://en.wikipedia.org/wiki/Palindromic_number)
> [Online bitwiseCmd tool](https://bitwisecmd.com/)
>
**Acceptance criteria:**
1. Validate input, accept only positive integers that can be stored within two-bytes.
2. Detect if the binary representation is a palindrome.

## Examples

Input:
`65535`

Output:
`It is a palindrome`

--

Input:
`65536`

Output:
`Invalid number. Too large to fit in two-bytes.`

--

Input:
`-11`

Output:
`Invalid number. Negative numbers are not allowed.`

--

Input:
`33153`

Output:
`It is a palindrome`

--

Input:
`64238`

Output:
`It is NOT a palindrome`

# 3. Geometry

As a user,
I want to enter a sphere's radius (in meters),
So that I can calculate its diameter, surface, and volume.

**Important**: You must use a class and implement the 3 methods.

**Acceptance criteria**
1. validate input, accept only positive numbers below 100.
2. display rounded results to two decimals.

## Examples

Input:
`-1`

Output:
`Invalid radius length.`

--

Input:
`105`

Output:
`Invalid radius length.`

--

Input:
`10`

Output:

Diameter: 20 m
Surface: 1256.64 mp
Volume: 4188.79 mc