You'll need to use direct input to read the keys. Though you will probably need to at least use some ion calls, like ionFastCopy to draw the graph buffer and ionPutSprite to draw a sprite to the screen. You could write your own sprite routine that wouldn't be too hard if you kept it aligned (meaning you can only draw to x multiples of
. Writing your own fastcopy routine isn't too hard if you know how the LCD ports work, but it's probably beyond the scope of this project.
You can use direct input to either read the numbers 0-9, if the number is correct, display a check sprite or something, if in correct, display an x sprite. You can also use the up and down arrows to increase and or decrease the number you want to choose.
Doing this without any external routines makes this program much more complicated. That or much more boring, as nothing will get drawn to the screen. The screen will be blank until you guess the correct number and then exit.
