We will be learning about the getKey function and how to create a controlled movement in this program.
Starting Out Edit
There are a few steps to ensure that your program will run smoothly:
Check if you have the RAM to hold a program Edit
Click on 2nd then MEM above the + sign. Make Sure that you have at least 500 RAM too use. If you don't i suggest you archive something by pressing 2 then 1 then press enter to anything that doesn't have a star next to it.
Creating the program Edit
Click the PRGM key then use the right arrow until NEW is highlighted. You should get a screen like this:
Go ahead and enter any name you want. Must be only A-Z, no numbers.
The Program Edit
PROGRAM:MOVER :ClrHome :1→Y :1→X :Lbl 1 :Output(Y,X,"O" :getKey→G :If G=0 :Goto 1 :ClrHome :If G=25 :Y-1→Y :If G=34 :Y+1→Y :If G=24 :X-1→X :If G=26 :X+1→X :If X=0 :X+1→X :If Y=0 :Y+1→Y :If X=17 :X-1→X :If Y=9 :Y-1→Y :Goto 1
PROGRAM:MOVER :ClrHome :1→Y :1→X
Setup the variables and clear the screen.
This is used to create a loop.
This prints an "O" at the O's current position.
Get a key and store it in G.
If G is 0, a key wasn't pressed, so go back and wait for a key to be pressed.
Clear the screen so a new "O" can be printed.
:If G=25 :Y-1→Y :If G=34 :Y+1→Y :If G=24 :X-1→X :If G=26 :X+1→X
Move the O in a direction depending on which key was pressed.
:If X=0 :X+1→X :If Y=0 :Y+1→Y :If X=17 :X-1→X :If Y=9 :Y-1→Y
If the O would have been off-screen, put it back on the screen.
Go back to the begining of the loop.
The user will be able to move a little circle around the screen.
You can make your circle go through the side of the screen if you change this part of the program (changes are boldened).
... :If X=0 :16→X :If Y=0 :8→Y :If X=17 :1→X :If Y=9 :1→Y :Goto 1
This is a much shorter program that does the exact same thing. It uses the properties of booleans to eliminate several of the If statements in the original.
PROGRAM:MOVER :ClrHome 1→A 1→B :While 1 :Output(A,B,"O :Repeat Ans :getKey→K :End :Output(A,B," //1 space to erase the O for update :B+(Ans=26 and B<16)-(Ans=24 and B>1→B :A+(K=34 and A<8)-(K=25 and A>1→A :End