Visual basic data types software#
Visual basic data types code#

Variables are initialized when they are declared, according to their type. If the form is loaded again, its variables are initialized, as if it is being loaded for the first time. Note that variables declared in a module and outside a procedure take effect when the form is loaded and ceases to exist when the form is unloaded. This option is no longer available with the versions of VB.NET. In VB6 we could declare all the variables in a procedure as static by prefixing the procedure definition with the keyword Static. We can also declare them in the function with the Static keyword, as shown below. We must declare the variables RunTotal and NumofItems outside the function so that their values are preserved between calls.

An example is shown below.įunction RunAvg(ByVal dblValue As Double) As Double Using the function RunAvg(), we can keep a running value in memory. With the Static keyword we can force a local variable to preserve its value between procedures. If a procedure calls another procedure, its local variables retain their values while the called procedure is running. When the same procedure is called again the local variables are recreated and initialized. When the procedure ends, the local variables cease to exist and the allocated memory is returned to the system.

Local variables, declared within procedures with the Dim or Private statement, are alive as long as the procedure.

Visual basic data types software#

Variables declared as Public exist for the lifetime of the software program. This is in addition to to type and scope. The Lifetime of a VariableThe period which a variable holds a value is called the lifetime of a variable. Public Class class1 Shared x As Integer Shared Sub New()

Visual basic data types code#

This is called a local variable because it the variable´s scope is limited to the particular procedure.įollowing is the vb code for the Click event of a Button to calculate the sum of all numbers in the range 0 to 50. When a variable is declared within a procedure, only that procedure has access to that variable. Along with a type, a variable also has a scope. Scope is the section of the software program in which the variable is visible and can be manipulated. For example the variable names strName, strname, STRNAME all refer to the same variable in the code. Variables in VB 2005 are case insensitive. The Decimal data type is new to VB.Net, and you use it when you want to control the accuracy of the calculations in terms of number of decimal digits. The new Integer data type is the same as the long data type of VB6 The VB.Net Long data type is new and can represent extremely large integer values. The Short data type is the same as the integer data type of vb6. The double type can represent these numbers more accurately than the single type and it is used almost exclusively in scientific calculations. Numeric variablesAll programming languages provide a variety of numeric data types, including the following:ĭecimal, Single and Double are the three basic data types for storing floating point numbers. Numeric variables store numbers, string variables stores text and Object variables store any type of data. The two major variable categories are numeric and string. Types of variablesVisual Basic recognizes the following five categories of variables. This statement is equal to the following two statements. The following line declares an integer variable and initialize it to 35. Variable initialization We can also initialize variables in the same line that declares them. A variable that holds characters is different from a variable that holds numbers.

This way the compiler can generate the code that handles the variables most efficiently. When we declare a variable we are actually telling the compiler the type of data we intend to store in each variable. One of the new terms in the VB 2005 documentation is 'strictly typed', which means that a variable has a specific type and you cannot store a value of different type to the variable. When we declare a variable, we must also specify its type. Microsoft VB compiler throws an exception if it comes across an undeclared variable. Net and 2005, variables should be declared by default.

If the compiler is informed of all the variables and their types, it can produce the most compact and efficient code. In a program, variables must be declared in advance. They also store and also possess a value.ĭeclaring VariablesTo declare a variable use the Dim statement followed by the variables name, As keyword, and its type. In todays programming languages variables are not just names or placeholders for values. A variable has a name and a value and stores values during program execution.