80 PRINT CHR$(17): HOME : HTAB 15: PRINT "HEXADDITION": HTAB 9: PRINT "BY DAVID HICKEY-SCHIAPPA": HTAB 1: PRINT "COPYRIGHT(C) 1990 MINDCRAFT PUBL. CORP.": VTAB 22: PRINT "press any key to start": VTAB 8
90 POKE -16368,0
100 FOR TT = 1 TO 5: IF PEEK( -16384) <128 THEN FOR HT = 15 TO 25: HTAB HT: PRINT "+";: POKE -16336,0: FOR ET = 1 TO 100: NEXT : HTAB HT: PRINT " ";: NEXT : NEXT
110 FOR HT = 15 TO 25: HTAB HT: PRINT "+";: NEXT : PRINT : PRINT
120 POKE -16368,0
130 REM
140 PRINT "This program will add or subtract two": PRINT "HEX numbers of 5 digits or less each.": PRINT : PRINT "Only valid HEX numbers are accepted.": PRINT "If you make a mistake, <ESC> to reenter"
150 POKE 34,14: REM GET INPUT
160 CLEAR :HX$ = "0123456789ABCDEF": VTAB 15: HTAB 1: CALL -958:NM$ = "": FOR X = 1 TO 40: PRINT "-";: NEXT : PRINT : PRINT "Enter the HEX numbers (<RET> to accept)"
170 PRINT "First number: $";
180 REM GET FIRST NUMBER
190 POKE -16368,0: GET TN$: IF TN$ = CHR$(27) THEN AH$ = "": CALL -1008: HTAB 16: CALL -958: GOTO 190: REM IF <ESC> START OVER
200 IF TN$ = CHR$(13) AND LEN(AH$) >0 THEN NM$ = AH$: GOSUB 530:AD = CH:TN$ = "": GOTO 250
210 IF TN$ = CHR$(13) GOTO 190
220 GOSUB 700: GOSUB 730: PRINT TN$;: IF TN$ = "" THEN PRINT CHR$(7);: GOTO 190: REM CHECK FOR CASE & VALIDITY, & PRINT DIGIT
230 AH$ = AH$ +TN$: IF LEN(AH$) >5 THEN VTAB 18: HTAB 1: CALL -958: PRINT CHR$(7); CHR$(7);: INVERSE : PRINT "NUMBER TOO LONG!": NORMAL : FOR ET = 1 TO 2000: NEXT :AH$ = "": VTAB 18: HTAB 1: CALL -958: GOTO 170