' Visual Basic 2008 9.0 .NET Examples - Introduction to Procedures - Procedures and Functions : 
Module Example1
    Sub Main()
        Dim menu As Char
        Dim value As Decimal
        '
        Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ")
        menu = Console.ReadLine()
        Do Until menu = "1"c OrElse menu = "2"c
            Console.WriteLine("An error occurred, please try again.")
            Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ")
            menu = Console.ReadLine()
        Loop
        '
        Console.Write("Value : ")
        value = Console.ReadLine()
        Do Until value > 0
            Console.WriteLine("An error occurred, please try again.")
            Console.Write("Value : ")
            value = Console.ReadLine()
        Loop
        '
        If menu = "1"c Then
            Console.WriteLine(value & " centimetres is " & value * 0.3937 & " inches")
        Else
            Console.WriteLine(value & " inches is " & value * 2.54 & " centimetres")
        End If
        '
        Console.ReadLine()
    End Sub
End Module
Module Example2
    Sub Main()
        Dim menu As Char
        Dim value As Decimal
        '
        Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ")
        menu = Console.ReadLine()
        Do Until menu = "1"c OrElse menu = "2"c
            ShowError()
            Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ")
            menu = Console.ReadLine()
        Loop
        '
        Console.Write("Value : ")
        value = Console.ReadLine()
        Do Until value > 0
            ShowError()
            Console.Write("Value : ")
            value = Console.ReadLine()
        Loop
        '
        If menu = "1"c Then
            Console.WriteLine(value & " centimetres is " & value * 0.3937 & " inches")
        Else
            Console.WriteLine(value & " inches is " & value * 2.54 & " centimetres")
        End If
        '
        Console.ReadLine()
    End Sub
    Sub ShowError()
        Console.WriteLine("An error occurred, please try again.")
    End Sub
End Module
Module Example3
    Sub Main()
        Dim menu As Char
        Dim value As Decimal
        '
        Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ")
        menu = Console.ReadLine()
        Do Until menu = "1"c OrElse menu = "2"c
            ShowMenuError()
            Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ")
            menu = Console.ReadLine()
        Loop
        '
        Console.Write("Value : ")
        value = Console.ReadLine()
        Do Until value > 0
            ShowValueError()
            Console.Write("Value : ")
            value = Console.ReadLine()
        Loop
        '
        If menu = "1"c Then
            Console.WriteLine(value & " centimetres is " & value * 0.3937 & " inches")
        Else
            Console.WriteLine(value & " inches is " & value * 2.54 & " centimetres")
        End If
        '
        Console.ReadLine()
    End Sub
    Sub ShowMenuError()
        Console.WriteLine("An illegal menu option is chosen.  Please try again.")
    End Sub
    Sub ShowValueError()
        Console.WriteLine("The value should be above zero.  Please try again.")
    End Sub
End Module
Module Example4
    Sub Main()
        Dim menu As Char
        Dim value As Decimal
        '
        Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ")
        menu = Console.ReadLine()
        Do Until menu = "1"c OrElse menu = "2"c
            ShowError("An illegal menu option is chosen.")
            Console.Write("1 centimetres -> inches / 2 - inches -> centimetres : ")
            menu = Console.ReadLine()
        Loop
        '
        Console.Write("Value : ")
        value = Console.ReadLine()
        Do Until value > 0
            ShowError("The value should be above zero.")
            Console.Write("Value : ")
            value = Console.ReadLine()
        Loop
        '
        If menu = "1"c Then
            Console.WriteLine(value & " centimetres is " & value * 0.3937 & " inches")
        Else
            Console.WriteLine(value & " inches is " & value * 2.54 & " centimetres")
        End If
        '
        Console.ReadLine()
    End Sub
    Sub ShowError(ByVal message As String)
        Console.WriteLine(message & "  Please try again.")
    End Sub
End Module
Module Example5
    Sub Main()
        ShowMenuError()
        '
        Example4.ShowError("message 1")
        '
        Dim someMessage As String = "message 2"
        Example4.ShowError(someMessage)
        '
        Example4.ShowError("message" & " " & "3")
        '
        Example4.ShowError(Console.ReadLine())
        '
        Console.ReadLine()
    End Sub
End Module
Module Example6
    Sub Main()
        Dim value As Integer = 5
        MultiplyBy10(value)
        Console.WriteLine("Main value : " & value)
    End Sub
    Sub MultiplyBy10(ByVal value As Integer)
        value *= 10
        Console.WriteLine("MultiplyBy10 value : " & value)
    End Sub
End Module
Module Example7
    Sub Main()
        Dim value As Integer = 5
        MultiplyBy10(value)
        Console.WriteLine("Main value : " & value)
        '
        MultiplyBy10(value + 1)
        Console.WriteLine("Main value : " & value)
    End Sub
    Sub MultiplyBy10(ByRef value As Integer)
        value *= 10
    End Sub
End Module
Module Example8
    Sub Main()
        ShowSum(1, 2)
        '
        Console.WriteLine()
    End Sub
    Sub ShowSum(ByVal value1 As Integer, ByVal value2 As Integer)
        Console.WriteLine(value1 + value2)
    End Sub
End Module
Module Exercise1Task
    Sub Main()
        Dim x As Integer = 4
        Dim y As Integer = 5
        Dim z As Integer = 6
        '
        Test(x, y, z + 1)
        '
        Console.WriteLine("Main x : " & x)
        Console.WriteLine("Main y : " & y)
        Console.WriteLine("Main z : " & z)
        Console.ReadLine()
    End Sub
    Sub Test(ByRef y As Integer, ByVal z As Integer, ByRef x As Integer)
        z ^= 2
        x += z
        y += z
        '
        Console.WriteLine("Test x : " & x)
        Console.WriteLine("Test y : " & y)
        Console.WriteLine("Test z : " & z)
    End Sub
End Module
Module Exercise2Task
    Sub Main()
        Dim number1, number2 As Integer
        '
        'Exercise2Solution.Input(number1, "Number 1 ? : ")
        'Exercise2Solution.Input(number2, "Number 2 ? : ")
        '
        'Exercise2Solution.ShowSmallest(number1, number2)
        '
        Console.ReadLine()
    End Sub
End Module
Module Exercise2Solution
    Sub Input(ByRef value As Integer, ByVal message As String)
        Console.Write(message)
        value = Console.ReadLine()
    End Sub
    Sub ShowSmallest(ByVal value1 As Integer, ByVal value2 As Integer)
        Dim smallest As Integer = value1
        If value2 < smallest Then smallest = value2
        Console.WriteLine("Smallest : " & smallest)
    End Sub
End Module

' Visit www.studyvb.com for more examples.  Copyright 2003-2008 De Wolf.