Screen Layout Examination

   10 REM Screen layout
   11 REM examination
   12 REM 
   20 REM Set up
   21 REM 
   30 INK 0: PAPER 7: BORDER 7: FLASH 0: BRIGHT 0: CLS 
   40 REM 
   41 REM Get values
   42 REM 
   50 INPUT "Enter byte (0>255) ";byte
   60 IF byte<0 OR byte>255 THEN GO TO 50
   70 INPUT "Enter color (0>255) ";color
   80 IF color<0 OR color>255 THEN GO TO 70
   90 REM 
   91 REM Alter Screen
   92 REM 
  100 FOR x=16384 TO 22527: POKE x,byte: NEXT x
  110 REM 
  111 REM Alter Colors
  112 REM 
  120 FOR x=22528 TO 23295: POKE x,color: NEXT x
  130 REM 
  131 REM Display Values
  132 REM 
  140 PRINT AT 2,4;"Byte = ";byte;AT 6,4;"Color = ";color;AT 10,4;"Press a key to alter"
  150 REM 
  151 REM Wait for keypress
  152 REM 
  160 IF INKEY$="" THEN GO TO 160
  170 GO TO 10