Rust Taskbook Level 8.7

Задание 1

Given a folder with files and subfolders, get an array of subfolder names from this folder.

Задание 2

Given a folder with files and subfolders. Get the names of all files in the folders and subfolders.

Задание 3

Given a text file, get the second line from this file.

Задание 4

Given an array of numbers, calculate the total number of digits 3 in all the numbers in the array.

Задание 5

Write a program that will generate the following array:

rust[
  "1",
  "12",
  "123",
  "1234",
  "12345",
}