For this exercise a function will be tested **with the exam own main**. However the student **still needs** to submit a structured program:
This means that:
- The package needs to be named `package main`.
- The submitted code needs one declared function main(```func main()```) even if empty.
- The function main declared needs to **also pass** the `Restrictions Checker`(illegal functions tester). It is advised for the student to just empty the function main after its own testings are done.
- Every other rules are obviously the same than for a `program`.
- Write a function that simulates the behaviour of the `Itoa` function in Go. `Itoa` transforms a number represented as an`int` in a number represented as a `string`.
- For this exercise the handling of the signs + or - **does have** to be taken into account.
