' converting a decimal integer to a binary string
' BCX basic
'
 
'
' postfix $ indicates a string variable
' could be written as:  dim A as String
'
DIM A$
 
 
A$ = dec2bin$(123)
PRINT "decimal 123 = binary ", A$
 
A$ = dec2bin$(255)
PRINT "decimal 255 = binary ", A$
 
pause  ' wait
 
 
'
' postfix $ in function name indicates that the function returns a string
' could be written as:  function dec2bin Optional (a, digits=0) as String
' keyword Optional indicates parameter digits is optional and defaults to 0
' variables declared within the function are local
'
FUNCTION dec2bin$ Optional (a, digits=0)
  DIM k, tmp, t  ' default to integer variables
  DIM T$         ' string variable
 
  ' don't know the number of digits in a, so figure it out
  IF digits = 0 THEN   
    tmp = a
    WHILE tmp > 0
      tmp = tmp >> 1   ' shift right by 1 place
      digits++         ' increment by 1, same as: digits = digits + 1
    WEND
  END IF
 
  t = 1
 
  ' do the conversion to zeros and ones
  FOR k = 1 TO digits
    tmp = a AND t
    IF tmp = 0 THEN
      T$ = "0" & T$
    ELSE
      T$ = "1" & T$
    END IF
    t = t << 1    ' shift left by 1 place
  NEXT
 
  FUNCTION = T$   ' result is in T$, return this
END FUNCTION