Subprocedures are those procedures that do not yield any value. When a program starts, control is passed to the Main Sub procedure, which then executes any other statements in the program's body.
Defining Sub Procedures
The Sub statement is used to declare a sub procedure's name, parameters, and body. The Sub statement has the following syntax:
[Modifiers] Sub SubName [(ParameterList)]
[Statements]
End SubWhere,
- Modifiers − indicate the procedure's access level; acceptable options include Public, Private, Friend, Protected, Protected Friend, and information about overloading, sharing, overriding, and shadowing.
- SubName – is the name of the Sub
- ParameterList – gives the list of the parameters
Passing parameters by value
This is the standard approach for supplying parameters to a method. When a method is called in this way, a new storage location is established for each value parameter. The actual parameter values are copied into them. As a result, changes to the parameter within the method have no effect on the argument.
The reference parameters are declared in VB.Net using the ByVal keyword.
Using a Reference to Pass Parameters
A reference parameter is a pointer to a variable's memory location. In contrast to value parameters, when you pass parameters by reference, no new storage place is generated for these parameters. The reference parameters are stored in the same memory location as the method's actual arguments.
The reference arguments are declared in VB.Net using the ByRef keyword.
