Futurebasic/Language/Reference/and

And

Operator

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Syntax

result& = exprA {and | &&} exprB

Description

Expression exprA and expression exprB are each interpreted as 32-bit integer quantities. The and operator performs a "bitwise comparison" of each bit in exprA with the bit in the corresponding position in exprB . The result is another 32-bit quantity; each bit in the result is determined as follows:

Bit value in exprA	Bit value in exprB	Bit value in result&
0	0	0
1	0	0
0	1	0
1	1	1

Example

In the following example, expressions are evaluated as true or false before a decision is made for branching. The logical expression time>7 is true, and is therefore evaluated as -1. The expression time<8.5 is false, and is therefore evaluated as 0. Then the bitwise comparison (-1) and (0) is performed, resulting in zero. Finally, the long if statement interprets this zero result as meaning "false," and therefore skips the first print statement.

time = 9.5
long if time > 7 and time < 8.5
   print "It is time for breakfast!"
xelse
   print "We have to wait 'til noon to eat!"
end if

The example below shows how bits are manipulated with AND:

defstr long
print bin$( 923 )
print bin$( 123 )
print "--------------------------------"
print bin$( 923 and 123 )

program output:

00000000000000000000001110011011
00000000000000000000000001111011
--------------------------------
00000000000000000000000000011011

Notes

In a statement like if expr1 and expr2 then..., it is possible for "expr1 and expr2" to be false even though each individual expr is evaluated as true. Consider this example:

JoeIsHere = 16
FredIsHere = 2
if JoeIsHere then print "Joe's here" else print "Joe's gone"
if FredIsHere then print "Fred's here"¬
  else print "Fred's gone"
long if JoeIsHere and FredIsHere
  print "They're both here"
xelse
  print "They're NOT both here!"
end if