problem.txt

OCR Kata Requirements

1. Accepts four strings of characters ("lines") and returns a
   nine-digit account number as a string. Like this:
        " _   _   _   _   _   _   _   _   _  "
        "|_| |_| |_| |_| |_| |_| |_| |_| |_| "
        "|_| |_| |_| |_| |_| |_| |_| |_| |_| "
        "                                    "
   Example returns: "888888888    "

2. Accepts more than one account number in a single set of strings (so, more than 4).

3. Returns ? for an invalid character.

4. Returns ILL when it contains invalid character. "888888?88 ILL"


YOUR MISSION:

Implement a checksum.

    account number:  6  6  4  3  7  1  4  9  5
    position names:  d9 d8 d7 d6 d5 d4 d3 d2 d1

    checksum calculation:
    (1*d1+ 2*d2 + 3*d3 + ... + 9*d9) mod 11 = 0

    Example returns: "664371495 ERR"

        " _   _       _   _           _   _  "
        "|_  |_  |_|  _|   |   | |_| |_| |_  "
        "|_| |_|   |  _|   |   |   |  _|  _| "
        "                                    "