BASIC OPERATORS Visual Basic also provides operators for
mathematical, comparison and logical calculation. In general, the program evaluates mathematical expressions in the following order: From left to right Follows the rules of precedence from basic math
Here is the list, from highest precedence to lowest:
Exponentiation (^) Multiplication and division (*, /) Integer Division (\) Modulus (Mod) Addition and subtraction (+, -)
BASIC OPERATORS Example Multiplication and division are performed first from left to right. Then addition and subtraction are performed. For example, 5 + 10 * 3 = 5 + 30 = 35. You can change this order of precedence by using parentheses. For example, (5 + 10) * 3 = 15 * 3 = 45. If you are unsure of the order of precedence, it is a good idea to clarify your intentions with parentheses.
ARRAYS By definition, an array is a list of variables, all with
the same data type and name. When we work with a single item, we only need to use one variable. However, if we have a list of items which are of similar type to deal with, we need to declare an array of variables instead of using a variable for each item. For example, if we need to enter one hundred names, instead of declaring one hundred different variables, we need to declare only one array. We differentiate each item in the array by using subscript, the index value of each item, for example name(1), name(2),name(3) .......etc.
ARRAYS We could use Public or Dim statement to
declare an array just as the way we declare a single variable. The Public statement declares an array that can be used throughout an application while the Dim statement declares an array that could be used only in a local procedure. The general format to declare an array is as follow: Dim arrayName(subs) As dataType Where subs are indicates the last subscript in the array.
ARRAYS Example
Dim CusName(10) As String Statement above will declare an array that consists of 10 elements if the statement appear in the declaration area, starting from CusName(1) to CusName(10). Otherwise, there will be 11 elements in the array starting from CusName(0) through to CusName(10)
Example
Dim Count(100 to 500) As Integer Statement above declares an array that consists of the first element starting from Count(100) and ends atCount(500)
MAKING DECISIONS CONDITIONAL STATEMENTS So far, all the programs we have worked on display menus, objects and dialog boxes on the screen in response to an action from the user, such as clicking a command button. Now, we will learn to use decision statements to compare variables, properties and values, and to execute one or more statements based on the results.
MAKING DECISIONS If/Then STATEMENT
Visual Basic provides an If/Then statement that you can use to make decisions in program. A decision “chooses” between different program paths depending on whether a specified condition is true or false.
Example If x = 7 Then result. text = “7 is a lucky number” will produce an output with the message “7 is a lucky number” if the variable x equal to 7. Otherwise there is no output.
MAKING DECISIONS If/Then/Else STATEMENT From the example above, to also produce an output in the event that x is not equal to 7, add an Else statement: If x = 7 Then result. text = “7 is a lucky number” Else result. Text = “try again” will produce the message “try again” in an output box if variable x is not equal to 7.
MAKING DECISIONS  The syntax for a conditional statement is If condition Then doThis [Else doThat] the Else part is optional.
 In conditional statements, comparison operators are usually used to make comparisons.