Directions: On the lines below, write the new contract and purpose for update-danger-2
, so that it produces a Posn instead of a Number. Then complete the Design Recipe.
Contract and Purpose Statement |
Every contract has three parts…
_______________:______________->____
_______________________________________________________________________________________________________________
Examples |
Write some examples, then circle and label what changes…
(EXAMPLE (_______________ ____)______________________________)
(EXAMPLE (_______________ _____)_______________________________)
Definition |
Write the definition, giving variable names to all your input values…
(define (_______________ ____)
_______________________________)
Adding Your New Function to Your Game File
1 Find update-danger
in your game file.
2 Directly beneath it, add update-danger-2
(including contract, purpose, examples, and definition) to your game file.
3 Scroll down to the very end of your game file and find the following PROVIDED CODE.
(define g (make-game TITLE TITLE-COLOR
BACKGROUND
DANGER update-danger
TARGET update-target
PLAYER update-player
mystery update-mystery
*distances-color* line-length distance
collide? onscreen?))
(play g)
4 Change update-danger
to update-danger-2
in the list and click "Run" so that your program will use your new function with two-dimensional movement, instead of the old function with one-dimensional movement.
Note: If, at any point, you would like to use the old function, all you have to do is change this list so that it says update-danger
instead of update-danger-2
!
These materials were developed partly through support of the National Science Foundation,
(awards 1042210, 1535276, 1648684, and 1738598).
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