Binary - Decimal Converter VB

Question

I don't know what equation vb will recognise for my code. to work. The user chooses weather to enter a decimal number or binary. It will then use an equation to convert that number. I have started the decimal but then got stuck, with what equation to use.

This is the code:

Module Module1

Sub Main()
    Dim userchoice As String
    Dim numberchoice, numchoice, newnumber As Integer
    Console.WriteLine("Please choose weather to convert 1) decimal to Binary or 2)Binary to decimal.")
    userchoice = Console.ReadLine()
    If userchoice = 1 Then
        Console.WriteLine("You are converting from a Decimal - Binary")
        Console.WriteLine("Please enter the number,")
        numberchoice = Console.ReadLine()
    End If
    If numberchoice > 128 Then
        Console.WriteLine("1")
        newnumber = numberchoice - 128
    End If
    If newnumber > 64 Then
        Console.WriteLine("1")
        newnumber = newnumber - 64
    End If
    If numberchoice > 32 Then
        Console.WriteLine("1")
        newnumber = newnumber - 32
    End If
    If numberchoice > 16 Then
        Console.WriteLine("1")
        newnumber = newnumber - 16
    End If
    If numberchoice > 8 Then
        Console.WriteLine("1")
        newnumber = newnumber - 8
    End If
    If numberchoice > 4 Then
        Console.WriteLine("1")
        newnumber = newnumber - 4
    End If
    If numberchoice > 2 Then
        Console.WriteLine("1")
        newnumber = newnumber - 2
    End If
    If numberchoice > 1 Then
        Console.WriteLine("1")
        newnumber = newnumber - 1
    End If
    Console.ReadLine()

    If userchoice = 2 Then
        Console.WriteLine("You're converting from Binary - Decimal")
        Console.WriteLine("Please enter the binary number,")
        numchoice = Console.ReadLine()
    End If
End Sub
End Module

You should firstly switch option strict on and fix those errors. Secondly you need to understand that you cannot convert a decimal number to binary: http://stackoverflow.com/questions/1089018/why-cant-decimal-numbers-be-represented-exactly-in-binary — Matt Wilko, Nov 12 '15 at 12:16
So, what are you asking for? An algorithm to convert binary to decimal and vice versa? Apart from that, the term `Dim numchoise, decimalanswer As Integer` only declares one Integer (decimalanswer) and also one Variant (numchoice) — EngJon, Nov 12 '15 at 12:17
@EngJon Yes, I am asking for an algorithm to convert binary to decimal and vice versa. How to I get it to declare more than one integer. Also the as integer bit has an error : 'Is' operator does not accept operands of type 'Integer'. Operands must be reference or nullable types. and the decimal below says - 'Decimal' is a structure type and cannot be used as an expression. — Newbie Coder, Nov 12 '15 at 12:26
Your ElseIf aren't doing what you want them to do, I would suggest you put a breakpoint and look at what is happening. — the_lotus, Nov 12 '15 at 12:38
@OliverLeadbitter You should do some research to see if the algorithm you want has already been written about. Please see [How do I ask a good question?](http://stackoverflow.com/help/how-to-ask) (Also, the spelling you want is "whether".) — Andrew Morton, Nov 12 '15 at 12:53

score 0 · Answer 1 · answered Nov 12 '15 at 17:14

This is what you seek:

Module Module1

Sub Main()
    While True
        Console.WriteLine("Please choose whether to convert:")
        Console.WriteLine("1.) Decimal to Binary")
        Console.WriteLine("2.) Binary to Decimal")
        Dim userChoice As String = Console.ReadLine()
        If userChoice = 1 Then
            Console.WriteLine("Converting from Decimal to Binary.")
            Console.Write("Please enter a Decimal number: ")
            Dim decimalNumber = Console.ReadLine()
            Console.WriteLine(String.Format("Binary representation of {0} in Decimal is {1}.", decimalNumber, ToBinary(decimalNumber)))
        ElseIf userChoice = 2 Then
            Console.WriteLine("Converting from Binary to Decimal.")
            Console.Write("Please enter a Binary number: ")
            Dim binaryNumber = Console.ReadLine()
            Console.WriteLine(String.Format("Decimal representation of {0} in Binary is {1}.", binaryNumber, ToDecimal(binaryNumber)))
        Else
            Console.WriteLine("Please enter a correct value.")
        End If
        Console.WriteLine(Environment.NewLine + "-------------------------------" + Environment.NewLine)
    End While
End Sub

Function ToBinary(input As String) As String
    Return Convert.ToString(Int64.Parse(input), 2)
End Function

Function ToDecimal(input As String) As String
    Return Convert.ToString(Int64.Parse(input), 10)
End Function

End Module

Binary - Decimal Converter VB

1 Answers1