Visual Basic Declaring Variables

Declaring Variables

• Dim stands for Dimension, you are telling VB how big of space to set aside for your variable (the dimensions of the variable space)
• Value types hold their data directly
• Reference types only hold a pointer to the actual data somewhere else in memory
• All built-in numeric types are value types
• Use a data type with enough precision for the work you need to do
• {Enter Data Type Information}
• {Enter Variable Naming Information}
• Numeric variables default to 0 (zero)
• String variable default to an empty string
• Objects are initialized to Nothing (null)
• Constants never change during the program execution
• Constants can be any data type
• Usually all uppercase so they are easily seen when scanning code
• Implicit conversions are always allowed for widening conversions (where the source data type is less precise than the destination data type)
• Explicit conversions are for narrowing conversions
• Null means "never entered"
• Use ? after the variable name in the Dimension statement
• Boolean is a "Yes or No"/"True or False" type variable
• False always converts to/from zero
• Although discouraged, you can use a reserved word for a variable name by always surrounding it with brackets [ ]