' Conv2Dec.bas                    hh     Aug. 14/02
' convert 1 to 4 digit numbers in bases 2 to 9, to decimal
' an option is to add 1 to the number after it is converted


DEFINT A-Z
false = 0: true = NOT false
addflag = false: CLS

PRINT "Conv2Dec.bas           Convert Numbers to Decimal        hh              8/14/02"
LOCATE 25, 10: PRINT "Enter a 5 digit number to exit program";
LOCATE 4, 1

10 INPUT "Enter the base of the numbers you wish to convert to decimal (2 - 9) "; basenum
IF basenum < 2 OR basenum > 9 THEN GOTO 10

PRINT : PRINT "Do you wish to automatically add 1 to the number after conversion to decimal"
INPUT "Press 'Y' or 'Enter"; addflag$
IF addflag$ = "y" OR addflag$ = "Y" THEN addflag = true

DO
20 PRINT "Enter the base "; basenum; " number ";
INPUT test
test$ = STR$(test)

FOR i = 1 TO LEN(test$)                      ' test for maximum digit size
   x$ = MID$(test$, i, 1): x = VAL(x$)       ' extract digit  
   IF x > basenum - 1 THEN                ' the digit is too large for the base
      PRINT "** A digit is too large for the base **": GOTO 20
   END IF
NEXT i

IF LEN(test$) = 6 THEN END            ' exit program (5 digits + leading space)
IF LEN(test$) = 4 THEN GOTO short         ' leading zero or just 3 digits
IF LEN(test$) = 3 THEN GOTO shorter       ' 2 leading zeros or just 2 digits
IF LEN(test$) = 2 THEN GOTO realshort     ' 3 leading zeros or just 1 digit

w$ = MID$(test$, 2, 1): w = VAL(w$)       ' extract MSD from 4 digit number
x$ = MID$(test$, 3, 1): x = VAL(x$)       ' extract Middle digit
y$ = MID$(test$, 4, 1): y = VAL(y$)       ' extract next Middle digit
z$ = MID$(test$, 5, 1): z = VAL(z$)       ' extract LSD
GOTO outer

short:
w = 0
x$ = MID$(test$, 2, 1): x = VAL(x$)       ' extract MSD
y$ = MID$(test$, 3, 1): y = VAL(y$)       ' extract Middle digit
z$ = MID$(test$, 4, 1): z = VAL(z$)       ' extract LSD
GOTO outer

shorter:
w = 0
x = 0
y$ = MID$(test$, 2, 1): y = VAL(y$)       ' extract Middle digit
z$ = MID$(test$, 3, 1): z = VAL(z$)       ' extract LSD
GOTO outer

realshort:
w = 0
x = 0
y = 0
z$ = MID$(test$, 2, 1): z = VAL(z$)       ' extract LSD

outer:
IF addflag THEN
   PRINT "   Base"; basenum; test; " plus 1 = Decimal";
ELSE
   PRINT "   Base"; basenum; test; "  = Decimal";
END IF

result = w * basenum * basenum * basenum + x * basenum * basenum + y * basenum + z
IF addflag THEN PRINT result + 1 ELSE PRINT result

LOOP