Picas y Fijas

The game Spades and Fixed, or also known as Spades and Fames, consists of finding a number of 4 different figures, from 0 to 9.
The person who knows the number (in this case the application) returns some clues, known as spades and fixed,
to each attempt to guess the number.

SPADES:
They are the numbers that are in the number to guess, but are not in the proper position in the proposed number.

FIXED:
They are the numbers that are in the number to be guessed and are in the proper position in the proposed number.
Example:
Number to guess: 1234
Proposed number: 1542
Spades: 2 (The number 4 and the 2)
Fixed: 1 (The number 1)