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- .DEMO
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- ET
- TB
- F3
- RT
- RT
- DN
- DN
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- ET
- TB
- +This demo describes the game mode of the Roo environment. Press any key.
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- +Press a key every time you have read a message in this line.
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- +The condition of a game: We are given pictures drawn by an invisible program.
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- +We have to create a program drawing the same pictures.
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- +THE MAIN IDEA: Every concept may be taught by using a series of games.
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- +The following game shows the concept of a program.
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- +This particular game is very easy. Even 4-5 years old kids may play it.
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- ^T
- BS BS BS BS BS BS BS BS BS BS
- :linear
- ET
- Y
- +The pattern program has been loaded into the "black box".
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- +The number of hearts reflects the level of complexity of the game.
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- +You are being given the condition of the game, that is the initial positions...
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- +...and the corresponding pictures. The red arrow shows the initial position.
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- +Press F1 to look at the resulting picture.
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- F1
- +The condition of game is given. It is easy to tell that...
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- +...the pattern program consists of 4 commands: TURN, TURN, HOP, STEP.
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- +So here is the program:
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- +
- #
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- F3
- F3
- F1
- F2
- +Is it a solution? You may check it. Press TAB to switch the F-keys line.
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- TB
- +Press F6 and then F2 to find if this solution is correct.
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- F6
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- A F6 F2$
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- +OK, this game was too easy. The next one will be more complicated.
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- +It was solved by 9 years old kids at the second lesson devoted to branchings.
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- ^T
- BS BS BS BS BS BS BS BS BS
- :branch
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- +The purpose of this game is to show the concept of a branching.
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- +There are two initial positions (the first one you may see now) and...
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- +...two pictures. One has to create a program which will draw...
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- +...the first (the second) picture starting at the first (the second) position.
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- +Press F1 to see the first picture.
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- F1
- +Now press F1 twice to see the next initial position and the next picture.
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- F1
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- F1
- +The condition of the problem is given. Let us try to solve it.
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- #
- +Suppose we are not so smart as those 9 years old guys and made a wrong program.
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- UP UP UP UP UP UP UP
- ^Y ^Y ^Y ^Y ^Y ^Y ^Y
- :if Roo can move forward then\
- :turn\
- :turn\
- :turn\
- :hop\
- :step\
- :turn\
- :step\
- :step\
- :turn\
- :step\
- :otherwise\
- :turn\
- :step\
- :step\
- :the end of branching\
- +Let us try this program. Put Roo at the first initial position.
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- +For this purpose we have to recall the condition of the game. Press F6 and F1.
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- F6
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- A F6 F1
- +This is the first initial position. We do not need a result now, so press ESC.
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- +Now press F1 to carry out our program.
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- F1
- +Yes, it is not a square. Thus there is a bug in our program. Where is it?
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- +There are two possibilities to get a hint.
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- +First, you may look how the "pattern" program works. Just press F6 and then F3.
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- F6
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- A F6 F3$
- +...and from the other position.
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- F1
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- +This hint "costs" one heart.
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- +Another possibility is to compare our program with the pattern one.
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- +In order to compare press F6 and then F4.
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- F6
- +You will see the "pattern" Roo in the left pen and our Roo in the right one.
- F6
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- A F6 F4$
- +Each comparison "costs" two hearts.
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- #
- +You may solve the problem yourself now. Good bye.
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