getKey Program

Note: This page was originally created by IProgrammer on the TI-Basic wiki, and has been added here because TI-Basic wiki is in the process of being merged with this wiki. In addition to this page, only those pages which weren't already duplicated on this wiki were added.

We will be learning about the getKey command, and how to create a controlled movement in this program.

Starting Out

There are a few steps to ensure that your program will run smoothly:

Check if you have the RAM to hold a program

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 on anything that doesn't have a star next to it.

Creating the program

Click the PRGM key then use the right arrow until NEW is highlighted. You should get a screen like this:

PROGRAM
NAME=

Go ahead and enter any name you want. Must be only A-Z, no numbers.

Now for the commands

Lets go ahead and put in some commands. By now you should have a general understanding so I'll go through this pretty fast:

PROGRAM:MOVER    // Title
:ClrHome         // Clears screen
:1→Y       // Sets 1 to Y
:1→X       // Sets 1 to X
:Lbl 1             // Program Divider #1
:Output(X,Y,"O"  // Displays the character
:getKey→G  // Gets the key that the user is pressing
:If G=0  // IF G=0 then...
:Goto 1  // Go to top (looper)
:If G≠0  // If G≠0 then...
:ClrHome  // Clears the screen
:If G=25  // If G=Up then...
:Y-1→Y  // Y-1 to Y when up is pressed
:If G=34  // If G=Down then...
:Y+1→Y  // Y+1 to Y when down is pressed
:If G=24  // If G=Left then...
:X-1→X  // X-1 to X when left is pressed
:If G=26  // If G=Right then...
:X+1→X  // X+1 to X when right is pressed
:If X=0  // If X is less than the screen then...
:X+1→X  // X+1 to X to stop ERROR:DOMAIN
:If Y=0  // IF Y is less than the screen then...
:Y+1→Y  // Y+1 to Y to stop ERROR:DOMAIN
:If X=17  // IF X is greater than the screen then...
:X-1→X  // X-1 to X to stop ERROR:DOMAIN
:If Y=9  // IF Y is greater than the screen then...
:Y-1→Y  // Y-1 to Y to stop ERROR:DOMAIN
:Goto 1  // Goes up to the top (looper)

Result

The user will be able to move a little circle around the screen.

Conclusion

Way to go you made your first getKey program!

Optionals

You can make your circle teleport to the other side of the screen if you change this part of the program.

...
:If X=0  // If X is less than the screen then...
:X+16→X  // Move X to right side of the screen
:If Y=0  // IF Y is less than the screen then...
:Y+8→Y  // Move Y to bottom of the screen
:If X=17  // If X is greater than the screen then...
:X-16→X  // Move X to left side of the screen
:If Y=9  // If Y is greater than the screen then...
:Y-8→Y  // Move Y to top of the screen
:Goto 1  // Goes up to the top (looper)

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