Programming Fundamentals/Conditions/VB.NET

conditions.vb

' This program asks the user to select Fahrenheit or Celsius conversion
' and input a given temperature. Then the program converts the given 
' temperature and displays the result.
'
' References:
'     https://www.mathsisfun.com/temperature-conversion.html
'     https://en.wikibooks.org/wiki/Visual_Basic_.NET

Imports System

Public Module MyProgram
    Sub Main
        ' Main could either be an If-Else structure or a Select-Case structure

        Dim Choice As String
        Dim Temperature As Double
        Dim Result As Double
        
        Console.WriteLine("Enter F to convert to Fahrenheit or C to convert to Celsius:")
        Choice = Console.ReadLine()

        ' If-Else approach
        If Choice = "C" Or Choice = "c" Then
            Temperature = GetTemperature("Fahrenheit")
            Result = CalculateCelsius(Temperature)
            DisplayResult(Temperature, "Fahrenheit", Result, "Celsius")
        ElseIf Choice = "F" Or Choice = "f" Then
            Temperature = GetTemperature("Celsius")
            Result = CalculateFahrenheit(Temperature)
            DisplayResult(Temperature, "Celsius", Result, "Fahrenheit")
        Else
            Console.WriteLine("You must enter C to convert to Celsius or F to convert to Fahrenheit!")
        End If
        
        ' Select-Case approach
        Select Choice
            Case "C", "c"
                Temperature = GetTemperature("Fahrenheit")
                Result = CalculateCelsius(Temperature)
                DisplayResult(Temperature, "Fahrenheit", Result, "Celsius")
            Case "F", "f"
                Temperature = GetTemperature("Celsius")
                Result = CalculateFahrenheit(Temperature)
                DisplayResult(Temperature, "Celsius", Result, "Fahrenheit")
            Case Else
                Console.WriteLine("You must enter C to convert to Celsius or F to convert to Fahrenheit!")
        End Select
    End Sub

    Function GetTemperature(Label as String) As Double
        Dim Input As String
        Dim Temperature As Double
        
        Console.WriteLine("Enter " + Label + " temperature:")
        Input = Console.ReadLine()
        Temperature = Convert.ToDouble(Input)
        Return Temperature
    End Function

    Function CalculateCelsius(Fahrenheit As Double) As Double
        Dim Celsius As Double
        
        Celsius = (Fahrenheit - 32) * 5 / 9
        Return Celsius
    End Function

    Function CalculateFahrenheit(Celsius As Double) As Double
        Dim Fahrenheit As Double
        
        Fahrenheit = Celsius * 9 / 5 + 32
        Return Fahrenheit
    End Function

    Sub DisplayResult(Temperature As Double, FromLabel As String, Result As Double, ToLabel As String)
        Console.WriteLine(Temperature.ToString() + "° " + FromLabel + " is " + Result.ToString() + "° " + ToLabel)
    End Sub
End Module

Try It

Copy and paste the code above into one of the following free online development environments or use your own VB.NET compiler / interpreter / IDE.

• paiza.IO
• TutorialsPoint

See Also

• Wikibooks: Visual Basic .NET

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Programming Fundamentals/Conditions