nice and fast way to convert to binary?

[Agamemnus]

is there a nice and fast way of converting to binary without computing powers of 2 first?

Since this number will be very large, computing powers of two would take some time..

[Agamemnus]

I actually just answered my own question:

http://www.wikipedia.org/wiki/Binary

[Antoni Gual]

Dividing by two can be nice but if you want to be fast, pre-compute the powers of two...

[Agamemnus]

Not a likely option. I'll need something like 500 powers of two stored as strings..

[Antoni Gual]

Store the number as a binary (each char is a power of 256)

[na_th_an]

You can try the dividing/module method:

Code:

DECLARE FUNCTION ToBin$ (Number&)
PRINT ToBin$(853847394)

FUNCTION ToBin$ (Number&)
   Res$ = ""
   WHILE Number& > 0
      Remaining& = Number& AND 1
      Res$ = LTRIM$(RTRIM$(STR$(Remaining&))) + Res$
      Number& = Number& \ 2
   WEND
   ToBin$ = Res$
END FUNCTION

Note that the AND 1 means MOD 2, that is, the remaining of dividing (Number& \ 2), but way faster . If QB had shifts, Number& = Number&\2 could be changed by Number& = Number&>>1 (shift right 1 place) which would be much faster.

[Mango]

Note that the AND 1 means MOD 2, that is, the remaining of dividing (Number& \ 2), but way faster . If QB had shifts, Number& = Number&\2 could be changed by Number& = Number&>>1 (shift right 1 place) which would be much faster.

thanks for the pointer...I will try this tonight! I'll post the time savings, if they are significant![/quote]

[DrV]

One way to improve speed would be to avoid string concatenations. For example, this code (which computes powers of 2 each time, but it's just a demo ):

Code:

n% = 12345
s$ = SPACE$(8)
for i = 0 to 7
  mid$(s$, i + 1, 1) = n% and 2 ^ i
next i

print s$