1 Not Boolean expression
2 Not Integer expression
Description
The Not keyword is used in two different ways:
1. To perform a logical or boolean 'Not' of a logical value.If True, the value becomes False. If False, the value becomes True.
2. To perform a mathematical 'Not' of an integer in a bitwise fashion. The result is a bitwise 'Not' of the number - every bit value is reversed - 0 to 1 and 1 to 0.
Notes
If the boolean expression is calculated (as opposed to being a Boolean variable), then brackets are required to isolate it.
Related commands
And Boolean and or bitwise and of two arguments
Boolean Allows just True and False values
If Starts a conditional expression to determine what to do next
Or Boolean or or bitwise or of two arguments
Xor Boolean Xor or bitwise Xor of two arguments
Example code : Illustrate both types of Not usage
var
num1, num2 : Word;
begin
num1 := $2C; // Binary value : 0000 0000 0010 1100
// Not'ed value : 1111 1111 1101 0011 = $FFD3
// And used to return a Boolean value
if Not (num1 > 0)
then ShowMessage('num1 <= 0')
else ShowMessage('num1 > 0');
// And used to perform a mathematical NOT operation
num2 := Not num1;
// Display the result
ShowMessage('Not $2C = $'+IntToHex(num2,2));
end;
Show full unit code
num1 > 0
Not $2C = $FFD3