Af"l"l"0 100000 2;  === ALIEN-INVASION ===&R A modified version of the program}( in Computing Today (March 1980),2 written for NAS-SYS 1 & 8K BASIC< by L. N. Rodrigues.FP: A23018 3065: A,219:ZA$" A L I E N - I N V A S I O N "=d A1 (A$): 3026A,((A$,A,1)):fn 3200,31711: 3202,312: 3204,18351x 3206,10927: 3208,8179: 3210,233 4100,3200: 6,7"Do you need Instructions ? ";A(0)V A89 440: A1 14:: 6,2-"You are the only Defender of the"]" outpost planet Rigel. Your ship is"" the at the top of the screen."" Your task is to destroy as many of"" the Alien ships as possible, or die!"" They come in two types:"9" Short-Range Long-Range"`" "" *"" They move up from the bottom of the""" screen.":," G Press a to continue ... ";6A(0)@ A1 15::#J 1,2ST" Press to change the direction"q^" of your motion.":h" Press to launch you Laser"r" bolt.":|" Laser bolts will be de flected with"" a non-direct hit.":1" The Aliens speed-up the more you"H" destroy.":x" Press a to start game ... ";A(0) 3200,25311: === Set Up Variables ===:J35:R((1)423)  W2186 2954 64: W,148 W47,148:X2059:M1:T60) X2060 M1= X2103 M1d === Check for Direction Key ===v A82 560 M1 M1: 560&M10XXM: X,186: X1,32: X1,32: (X256)157 (X256)n 187 1100D (X704)42 KX640: 1110N FF0 610.X FF1 720: 500NbTT(JH):TT1: TTT 700jlN((1)3): N1 650v R,15:"": R,15:" " 660 R,15:"": R,15:"*"T0:R((1)423) 1,1:C (27): (27): 1,15 2890,148: 2937,148  2954,148: 3001,148FA(0): A32 FF1:FX64: 720P 500i RI1 LE1 1310tFF64A(0): A82 760 790 M1 M1: 790M1  === Direct Hit ? ===< (F)157 (F)187 HH1: 980  F128,32#* === Near Miss ? ===94 (F)135 880]> F64,148: F65,138: F1,152nH Q0 80:R F64,32: F65,32: F1,32\D1:RI1:FF1: 930f F128,32p (F)134 930z F64,148: F63,139: F1,152 Q0 80:# F64,32: F63,32: F1,326D1:LE1:FF1d F2954 FF0:D0:RI0:LE0: F64,32:r D1  F,11: F64,148: F128,32 === Destroy Alien Routine === F64,32: F128,32  Q0 1 F1,245: F64,141: F1,186* F,143: F63,151: F65,185M F1,206: F64,187: F1,158o F,150: F63,174: F65,220 F1,32: F64,32: F1,32 F,32: F63,32: F65,32$ Q:FF0. FK64 7208D0:{RI0:LE0: B === Destroy Defender Routine ===LKX256,V (K)186 1140B` K64,32: K,152TjKK64: 1110bt K64,32~ W1 20: K,185: O1 10: K,186: O1 10: O,W === End Game Printout ===: 10,5"You destroyed"H"of the Aliens.": 10,7 H2H H2H: 1220" 1230M"It is the best Score so far.": 1240j"The Best Score is ="H2{ 3200,31711 10,9:"Another Game ? ";A(0) A89 : 3200,25311 :J35:H0:D0:RI0:LE0:FF0: 460 === Rebound Bolt Routines ===. LE1 K65: 13307(K63A2FFKW< (F)148 1370kF F2953 1370vP 1380Z FK,32:FF0:D0:RI0:LE0:d (F)32 FK,32:HH1: 1400n F,46: FK,32: x (F1)187 (F1)157 FF1: 980!  (F)187 (F)157 980M  (F1)187 (F1)157 FF1: 980|  (F65)187 (F65)157 FF65: 980  (F63)187 (F63)157 FF63: 980  (F65)187 (F65)157 FF65: 980  === Variable List ===! A is Keyboard Response:! X is Position of DefenderZ! R is Position of Alieny! M is Direction Marker! FF is Fire Marker! F is the Bolt Position! K is the Alien Bolt Positi!on" RI is the Right Rebound Marker&" LE is the Left Rebound MarkerD" H is the Hit Counterd"" H2 is the Highest Score