Difference between revisions of "And"
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(→Bitwise operation: mention operands need to be ordinal and it is referred to as a "logical and" in the documentation.) |
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== Bitwise operation == | == Bitwise operation == | ||
− | Bitwise and sets a bit to 1 if and only if | + | Logical '''And''' (aka Bitwise And) requires ordinal operands and sets a bit in the result variable to 1 if and only if both of the corresponding bits in the operands are 1. |
=== Is power of two === | === Is power of two === |
Revision as of 05:47, 14 June 2016
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Boolean operation
And produces a value of true if and only if both of its operands are true.
Truth table
A | B | A and B |
---|---|---|
false | false | false |
false | true | false |
true | false | false |
true | true | true |
Bitwise operation
Logical And (aka Bitwise And) requires ordinal operands and sets a bit in the result variable to 1 if and only if both of the corresponding bits in the operands are 1.
Is power of two
function IsPowerOfTwo( const aValue : longint ): boolean;
var
x : longint;
b : boolean;
begin
b := false;
if aValue <> 0 then
begin
x := aValue - 1;
x := x and aValue;
if x = 0 then b := true;
end;
result := b;
end;
If you call IsPowerOfTwo(4) then you get true. If you call IsPowerOfTwo(5) then you get false .