Kata

Description:

Given a string, you need to write a method that order every letter in this string in ascending order.

Also, you should validate that the given string is not empty or null. If so, the method should return:

"Invalid String!"

Notes

• the given string can be lowercase and uppercase.
• the string could include spaces or other special characters like '# ! or ,'. Sort them based on their ASCII codes

Examples

"hello world" => " dehllloorw"
"bobby"       => "bbboy"
""            => "Invalid String!"
"!Hi You!"    => " !!HYiou"

Good luck! Hope you enjoy it