Logical Operators

Logical operators, described in the following, take Boolean (logical) values as operands and return a Boolean value.

OperatorDescription

&&

(Logical AND) Returns true if both logical operands are true. Otherwise, returns false. The Logical AND operator is used as follows:

expr1 && expr2

Returns expr1 if it converts to false. Otherwise, returns expr2.

||

(Logical OR) Returns true if either logical expression is true. If both are false, returns false. The Logical OR operator is used as follows:

expr1 || expr2

Returns expr1 if it converts to true. Otherwise, returns expr2.

!

(Logical negation) If its single operand is true, returns false; otherwise, returns true.

Example

Consider the following script:

v1 = "Cat";
v2 = "Dog";
v3 = false;
Console.Write("t && t returns " + (v1 && v2));
Console.Write("f && t returns " + (v3 && v1));
Console.Write("t && f returns " + (v1 && v3));
Console.Write("f && f returns " + (v3 && (3 == 4)));
Console.Write("t || t returns " + (v1 || v2));
Console.Write("f || t returns " + (v3 || v1));
Console.Write("t || f returns " + (v1 || v3));
Console.Write("f || f returns " + (v3 || (3 == 4)));
Console.Write("!t returns " + (!v1));
Console.Write("!f returns " + (!v3));

This script displays the following:

t && t returns Dog
f && t returns false
t && f returns false
f && f returns false
t || t returns Cat
f || t returns Cat
t || f returns Cat
f || f returns false
!t returns false
!f returns true