Bulls & Cows is a logical game for kids and adults, also known as Mastermind, 4digits or 1A2B. Your goal is to find the computers secret number with a minimum number of suggestions.
On each guess the game announces the number of "cows" and "bulls" in your suggestion. If the matching digits are on their right positions, they are "bulls", if they are on different positions, they are "cows". To win you must reveal the secret number.
Example: secret number is 8207
1st guess: 1234 (1 Bull)
The bull is 2 - digit is in the number and in the correct position
2nd guess: 1705 (1 Bull 1 Cow)
The bull is 0 - digit is in the number and in the correct position
The cow is 7 - digit is in the number and but in the wrong position
3rd guess: 8207 (4 Bulls)
All digits are bulls because they are all in the number and in the correct positions