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Tech Arsenal 1
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Tech Arsenal (Arsenal Computer).ISO
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tek-03
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qbasicpg.zip
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STEP-1.BAS
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BASIC Source File
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1989-08-31
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1KB
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38 lines
' STEP-1.BAS
' This program uses the illusion of zooming through space
' to demonstrate the STEP keyword.
CLS
CONST DELAY% = 200 ' controls how fast stars "shoot"
INPUT "Please enter a screen mode (0-13): ", modeNum%
SCREEN modeNum%
DO
PSET (160, 100), 0 ' set center (assumes 320 by 200
' resolution)
quad% = INT(RND(1) * 4) ' random number for quadrant from
' which the "star" will shoot
randX% = INT(RND(1) * 10) ' random number for column movement
randY% = INT(RND(1) * 10) ' random number for row movement
IF quad% = 0 OR quad% = 1 THEN ' normal movement is down;
randY% = -randY% ' reverse y value to move up
END IF
IF quad% = 0 OR quad% = 3 THEN ' normal movement is to right;
randX% = -randX% ' reverse x value to move to left
END IF
FOR i% = 1 TO 20
PSET STEP(-randX% * i%, randY% * i%) ' draw "star"
FOR j% = 1 TO DELAY% ' delay loop
NEXT j%
PRESET STEP(0, 0) ' erase "star"
NEXT i%
LOOP UNTIL INKEY$ <> ""