The Museum of HP Calculators
The Museum of HP Calculators
This program was first published in the HP-41C Users' Library Solutions: Games by Hewlett-Packard and is used here by permission.
This program is supplied without representation or warranty of any kind. Hewlett-Packard Company and The Museum of HP Calculators therefore assume no responsibility and shall have no liability, consequential or otherwise, of any kind arising from the use of this program material or any part thereof.
Hexapawn is a game which is programmed to learn from its mistakes. The game is played with chess pawns on a 3x3 board. Pawns may advance one square at a time or capture the opponent's pawns by moving diagonally one square. The game starts with the pawns positioned as follows:
Note the resemblance between the 41C digit keys and the board numbering. The three allowed opening moves for the first player (in this example, white) are 1 to 4 (keyed as 1.4), 2 to 5 (2.5), and 3 to 6 (3.6).
Black's three possible responses to white's 1.4 move are 8 to 4, 8 to 5, and 9 to 6.
Black can move diagonally and capture white (8 to 4), or he can move either pawns 8 or 9 straight ahead one square. The black pawn at 7 is blocked. Note that the only way a pawn can move to an open square is straight ahead. Also the only way a pawn can capture is by moving diagonally.
The game is won by advancing a pawn to the third row, capturing all of the opponent's pawns, or creating a position in which the opponent cannot move.
Moves are made by keying in the board position of the pawn to be moved, a decimal point, then the board position the pawn is to be moved to. The 41C does not check for illegal moves; therefore, you are on your honor not to cheat. The 41C selects its move at random, but if it is then punished, it remembers not to make that move in that situation. Thus, if the machine makes a poor move and is punished, it will not repeat the mistake.* Also, if the mirror image game is played, it will not make the mirror image of the poor move. If a point is reached in a game where all possible moves for a certain board configuration have received previous punishment, "NO MOVE" and "YOU WIN" is displayed, just as if there really were no move. If you cannot move, you can if you wish be a good sport and tell the 41C by keying 0 for your move. It will respond with "I WIN". If chess pawns are not available for visualization, different colored coins work well.
*Similarly, you can punish good moves to make it play a losing game.
Note: Requires 2 Memory Modules on HP-41C
|
Step |
Instructions |
Input Data/Units |
Keys |
Output Data/Units |
|
1 |
Enter program |
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2 |
Initialize type of game: human first, |
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[XEQ] HUMAN |
SEED? |
| or machine first. |
[XEQ] MACHINE |
SEED? |
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3 |
Key in a seed for the random number generator between 0 and 1. (Just hit [R/S] if a seed has been previously entered.) |
seed |
[R/S] |
READY (or) |
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|
( ) to ( ) |
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4 |
Key in your move FROM.TO |
F.T |
[R/S] |
( ) to ( ) |
| Repeat step 4 until game is over |
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5 |
OPTIONAL: After the 41C displays its move, punish it. |
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[E] |
AAAIIII... |
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6 |
To signify that you can't move |
0 |
[R/S] |
I WIN |
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7 |
To start a new game with the same player first and punishments remembered. |
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[A] |
READY (or) |
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|
|
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( ) to ( ) |
| Go to step 4 | ||||
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8 |
To start a new game with a different player first and/or forgetting punishments go to step 2. |
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Keystrokes: Display: [XEQ] [ALPHA] SIZE [ALPHA] 014 [XEQ] [ALPHA] MACHINE [ALPHA] SEED? .1111111111 [R/S] 8 to 5 1.5 [R/S] 7 to 4 (A bad move; therefore, punish) [E] AAAIIII... 5.8 [R/S] YOU WIN Start a new game with the 41C remembering its punishment. [A] 8 to 5 1.5 [R/S] 7 to 5 3.5 [R/S] 9 to 5 0 [R/S] I WIN
LINE KEYS 01LBL "MACHINE" 02 XEQ 01 Machine first 03 8388607 04 STO 01 05 3139583 06 STO 02 07 34314 08 STO 03 09 SF 05 10 GTO A 11
TO " 303 LASTX 304 FRC 305 10 306 * 307 ARCL X 308 AVIEW 309 GTO 30 310
R00 Seed R01 Possible moves R02 Possible moves R03 Possible moves R04 Trial move R05 Used R06 Used R07 Used R08 Current Move R09 Last move R10 Board R11 From R12 To R13 Counter
05 41C first / Human first 06 41C's move / Human's move 07 Mirror image / Normal game 08 First move 09 Used
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