Q(uick)BASIC Operator: NOT

Quick View

NOT Operator

The logical-complement operator belongs to the family of boolean operators

Worth knowing

Useful and cross-version information about the programming environments of QBasic and QuickBasic.

Syntax
  • result = expression1 boolean-operator expression2
Description/Parameter(s)
boolean-operator Any of the following Boolean operators:
NOT Bit-wise complement
AND Conjunction
OR Disjunction (inclusive "or")
XOR Exclusive "or"
EQV Equivalence
IMP Implication

Each operator returns results as indicated in the following truth table. T is true (nonzero); F is false (zero):

Expression1 Expression2 NOT AND OR XOR EQV IMP
T T F T T F T T
T F F F T T F F
F T T F T T F T
F F T F F F T T
  • Boolean operations are performed after arithmetic and relational operations in order of precedence.
  • Expressions are converted to integers or long integers before a Boolean operation is performed.
  • If the expressions evaluate to 0 or -1, a Boolean operation returns 0 or -1 as the result. Because Boolean operators do bit-wise calculations, using values other than 0 for false and -1 for true may produce unexpected results.
Syntax
  • result = numeric-expression1 NOT numeric-expression2
Description/Parameter(s)

The logical-complement operator evaluates each bit in numeric-expression, then sets the corresponding bit in the result according to the following table:

Bit in Expression Bit in Result
1 0
0 1

This inverts the bit values of any variable. If an integer variable has the value 0 (false), the variable becomes -1 (true), and vice-versa.

Syntax
  • result = NOT numeric-expression
Description/Parameter(s)

The logical-complement operator evaluates each bit in numeric-expression, then sets the corresponding bit in the result according to the following table:

Bit in Expression Bit in Result
1 0
0 1

This inverts the bit values of any variable. If an integer variable has the value 0 (false), the variable becomes -1 (true), and vice-versa.