IT 10 REVIEWER ANSWERS - PROCEDURES and ERROR HANDLING

1. What is a procedure?
	> A procedure is a block of Visual Basic statements enclosed by a declaration statement and a matching End declaration. All executable statements in Visual Basic must be within some procedure.

2. What are the different types of procedures?
	> The Sub procedure performs a task and then returns control to the calling code, but it does not return a value to the calling code.
	> The Function procedure performs a task and then returns control to the calling code. When it returns control, it also returns a value to the calling code.

3. Write the syntax for the following:
a. Sub Procedure
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	[Private/Public] Sub Subprocedure1(ByVal task As String)
 	   [sub statements to execute]
	End Sub
==========

b. Function Procedure
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	Function FunctionName [(ParameterList)] As ReturnType
	    [function statements to execute]
	    Return Value				// this code is needed when you want your function to return a value
	End Function
==========

4. What is the difference between Sub and Function procedures?

5. How does a function procedure return a value?

6. How do you invoke a Sub procedure?
	> Sub procedures can be executed only as a single statement in a VB.NET code.
	example:	exampleSub()
7. How do you invoke a Function procedure?
	> Sub procedures can be executed only as a single statement in a VB.NET code.
	example:		exampleSub()
	example 2:		Dim testLength, testHypotenuse As Single
					testHypotenuse = hypotenuse(testLength, 10.7)

8. What is an exception?
	> An exception is a response to an exceptional circumstance (in short: errors) that arises while a program is running, such as an attempt to divide by zero.

9. Write the syntax of the Try…Catch… Statement.
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	Try
	   [statements to execute]
	   Dim strExampleCode = Example1.Text
	Catch ex As Exception
	   [statements to execute when an exception/error is caught]
	   MessageBox.Show(ex.ToString)			// This code opens a message box containing the Exception as a string.
	Finally
	   [statements to execute after the TRY CATCH]			// statements will still whatever the outcome is
	End Try
==========
NOTE: FINALLY Block is optional and you can end it all off with END TRY.

10. Give an example of an exception.
	> Invalid Input - Mismatch on input values and variable types (ex. Typing a character where an integer is expected)
	> Stack Overflow - memory heap or variables reached their limits or something
	> Null Reference - Stuff/Values/Variables mentioned can't be found or does not exist
	> Division by Zero - enough said.

11. How does a Try…Catch… statement work?
	> It "tries" to execute a set of statements and "catches" and exception or an error that occurred in the middle of the code execution.

12. What is the function of the finally code block?
	> To execute a certain set of commands no matter what results/outputs come out from the TRY CATCH statement.