the Queens puzzle

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Delphi program description and source code

Puzzle description

How many queens are needed minimally to cover all fields of the chessboard?
This program helps in two ways:
    - manually, by adding removing queens by mouseclicks
    - let the program search for solutions

Help information

Below is a reduced picture of the program at work:

Manual mode

    Click TRY to select manual mode.
    Click on a field to add or remove a queen.

    It is not possible to place a queen on an already covered field.
    The program issues a message if the puzzle is solved.

    Click RESET to remove all queens.

Program search

    Click SOLVE to select program mode.
    Select number of queens allowed.
    Click GO to start search process.
    At a solution click GO again to find more solutions.

    Click RESET to end the search process.

Have fun!