Programming languages have three types of operators: arithmetic, relational, and logical.

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Examples:

• Addition: 2 + 3

• Multiplication: 2 * 4

• Subtraction: 4 - 2

• Exponentiation:  2 ^ 4

• Real Division:  3 / 2   (equals 1.5)

• Integer Division: 3 \ 2  (equals 1) -- remainder is discarded

• Modulus: 6 Mod 4 (equals 2) -- result is the remainder when first number is divided by the second number. If either number is a floating-point number, the result is a floating-point number representing the remainder.

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Precedence of Arithmetic Operators

If multiple arithmetic operators are included in a single equation, the operations are performed in a specific order:

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Parentheses can be used to clarify the precedence of operators in an expression, or even alter the precedence.  Parentheses have a higher precedence than any operator.

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Expression Type

VB expressions have both a type and a value.

• For addition, subtraction, or multiplication, if either operand is real, the result is real.
  

• For real division (/), the result is real regardless of the types of the operands.
  

• For integer division (\), the result is integer regardless of the types of the operands.  
  

• For both integer division and modulus, both the operands are rounded to Integers (or Longs) before division is applied.

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Built-in Functions

• Int:  converts a real to an integer by truncating the decimal portion

  • Int(2/3) is equal to 0

  • Int(10.1) is equal to 10

  • Int(10.9) is equal to 10
    

• Val:  converts a string of numbers to a value

  • Val("23.45") is equal to 23.45

  • Val("13mmm2342") returns 13

Logical Operators

Logical operators can be used to test multiple conditions by combining simple conditions.

The logical operators are And, Or, and Not.

And and Or can only be used to test a complete condition. The following is an invalid statement:

If testCondition = 1 Or 2 Or 4 Then

Instead, a complete condition must be specified:

If ( testCondition = 1 ) Or
   ( testCondition = 2 ) Or
   ( testCondition = 4 ) Then

The same holds true for the And.  The following is invalid:

       If ( grade < 90 and >= 80 ) Then 

Similarly, you cannot write a VB statement like 

        If ( 90 < grade <= 80 ) Then

The correct syntax for such a statement is

        If ( grade < 90 ) And ( grade >= 80 ) Then

See the note on the evaluation of compound conditions and short circuiting....

Additional operators

Precedence of VB Operators