Operator Andalso (Short Circuit Conjunction)

Declare Operator AndAlso ( ByRef lhs As T1, ByRef rhs As T2 ) As Ret

result = lhs AndAlso rhs

lhs
T1
rhs
T2
Ret

Returns the short circuit-and (conjunction) of the two operands.

This operator evaluates the left hand side expression. If the result is zero, then zero is immediately returned. If the result is nonzero then the right hand side is evaluated, and the logical result from that is returned.
(for conversion of a boolean to an integer, false or true boolean value becomes 0 or -1 integer value)

The truth table below demonstrates all combinations of a short circuit-and operation, the '-' denotes that the operand is not evaluated.



Short-circuiting is performed - only expressions needed to calculate the result are evaluated.

The return type is almost always an Integer, of the value 0 or -1, denoting false and true respectively. Except if the left and right-hand side types are both Boolean, then the return type is also Boolean.

This operator cannot be overloaded for user-defined types.

'' Using the ANDALSO operator to guard against array access
'' when the index is out of range

Dim As Integer isprime(1 To 10) = { _
    _ ' 1  2  3  4  5  6  7  8  9  10
        0, 1, 1, 0, 1, 0, 1, 0, 0, 0 _
    }

Dim As Integer n
Input "Enter a number between 1 and 10: ", n

'' isprime() array will only be accessed if n is in range
If (n >= 1 And n <= 10) AndAlso isprime(n) Then
    Print "n is prime"
Else
    Print "n is not prime, or out of range"
End If

• This operator was not available in QB.
  
  

• OrElse
  
• And
  
• Operator Truth Tables