# Not Operator (Visual Basic)

**Visual Studio 2005**

Performs logical negation on a **Boolean** expression, or bitwise negation on a numeric expression.

result = Not expression

For **Boolean** expressions, the following table illustrates how result is determined.

If expression is | The value of result is |
---|---|

| |

| |

For numeric expressions, the **Not** operator inverts the bit values of any numeric expression and sets the corresponding bit in result according to the following table.

If bit in expression is | The bit in result is |
---|---|

1 | 0 |

0 | 1 |

Note |
---|

Since the logical and bitwise operators have a lower precedence than other arithmetic and relational operators, any bitwise operations should be enclosed in parentheses to ensure accurate execution. |

### Data Types

For a Boolean negation, the data type of the result is **Boolean**. For a bitwise negation, the result data type is the same as that of expression. However, if expression is **Decimal**, the result is **Long**.

### Overloading

The **Not** operator can be *overloaded*, which means that a class or structure can redefine its behavior when its operand has the type of that class or structure. If your code uses this operator on such a class or structure, be sure you understand its redefined behavior. For more information, see Operator Procedures.

The following example uses the **Not** operator to perform logical negation on a **Boolean** expression. The result is a **Boolean** value that represents the reverse of the value of the expression.

Dim a As Integer = 10 Dim b As Integer = 8 Dim c As Integer = 6 Dim firstCheck, secondCheck As Boolean firstCheck = Not (a > b) secondCheck = Not (b > a)

The preceding example produces results of **False** and **True**, respectively.

The following example uses the **Not** operator to perform logical negation of the individual bits of a numeric expression. The bit in the result pattern is set to the reverse of the corresponding bit in the operand pattern, including the sign bit.

Dim a As Integer = 10 Dim b As Integer = 8 Dim c As Integer = 6 Dim firstPattern, secondPattern, thirdPattern As Integer firstPattern = (Not a) secondPattern = (Not b) thirdPattern = (Not c)

The preceding example produces results of –11, –9, and –7, respectively.