MasterMind

MasterMind is a board game with two players; in this case the user choses the secret and the program does the guessing. Unfortunately, the board is not visualised. Here is a sample interaction:
examples> ./MasterMind
Welcome to Mastermind!
Choose your secret. Press return when ready.

My guess: Red Blue Blue Red
Answer (two integers): 1 1
My guess: Blue Black Yellow Red
Answer (two integers): 2 0
My guess: Green Black Red Red
Answer (two integers): 0 0
My guess: Blue Blue Yellow White
Answer (two integers): 3 0
My guess: Blue Blue Yellow Blue
Answer (two integers): 3 0
My guess: Blue Blue Yellow Yellow
Answer (two integers): 4 0
Yippee!
Do you want to play again? (y/n) n
examples> 
The program is too long to display here. We only note a few things: