Guess

A simple mind game.
Rules:
Single Player:
Application will generate 4 digit number and u have to guess that number.
If the matching digits are on their right positions, they are "Cows", if on different positions, they are "Bulls". Example:

Secret number: 4271
Opponent's try: 1234
Answer: 1 cows and 2 bulls. (The cows is "2", the bulls are "4" and "1".)

Challenge Your Friend:
Implicitly you have to add 4 digit number and pass mobile to your friend and let them guess your number.
Enjoy the game and let me know for any changes and bugs.

Email-hatimabde@outlook.com