I am trying to take the user input and assign it to a property defined in a class. When I run the program, it asks for user input as expected, but displays a different result. Can someone point out where my mistake is ?
I was trying to base my simple program on this tutorial
https://learn.microsoft.com/en-us/dotnet/core/tutorials/vb-with-visual-studio
but trying to extend it to classes.
I am using the latest version of Visual Studio and Visual Basic. It's a visual basic Console App
Module Module1
Sub Main()
Dim ClassInstance As New Class1()
Console.WriteLine("Input Property 1: ")
ClassInstance.Property1 = Console.Read()
Console.Write(ClassInstance.Property1)
Console.ReadKey(True)
End Sub
Public Class Class1
Public Property1 As Integer
Public Property2 As Integer
End Class
End Module
Expected output:
"Input Property 1:" |
User input 50 |
Output 50
Console.Read reads the next character from the input, and gives you that character's code. If, for instance, you typed 5 at the prompt1, Console.Read would return 53. Why? Because that's the ASCII/Unicode code for that character (in Unicode terms, it's U+0035, which is the same number represented in hexadecimal).
If you want to read multiple characters and interpret them as an integer, you should a) be using something other than Console.Read to take the input and b) use Int32.TryParse to try to turn it into a number (because users don't always give us the input we expect).
Something like:
Module Module1
Sub Main()
Dim ClassInstance As New Class1()
Console.WriteLine("Input Property 1: ")
Dim inp = Console.ReadLine()
Dim value as Int32
If Int32.TryParse(inp, value) Then
ClassInstance.Property1 = value
Console.Write(ClassInstance.Property1)
Console.ReadKey(True)
End If
End Sub
Public Class Class1
Public Property1 As Integer
Public Property2 As Integer
End Class
End Module
(With apologies if I've made syntax errors - my VB's quite rusty)
In reality, you'd probably want to write some form of loop that prompts for user input and doesn't terminate until it successfully parses. I think Do/While would fit there - but if you're going to prompt the user more than once, you probably would want to extract the "Loop until valid input received" code into a function that takes the prompt as a parameter.
More reading - ASCII/Unicode. For characters in the "7-bit ASCII" range, basic latin characters without accents, it doesn't make much difference which references you check
1And it doesn't matter if you carried on and typed any more characters, your program only asks for/gets one of them
Related
I'm working within Visual Basic console application.
I have created a number of mathematical features such as quadratic equation and prime factorisation.
However, my next task is to create a mathematical feature that you're able to enter and select the number of decimal places you wish to get your answers for the other mathematical features.
For example let's call this function decimalPoint:
You enter decimal point - you're asked how many decimal places you'd like your answers to. You chose 2.
You go back to the main menu and select quadratic equation, after inputting the coefficients then the output of the quadratic equation has to output in 2.d.p.
I'm able to ask the user for an input and just convert that into whatever d.p I need, but I don't know how to link it to other subs/functions.
So Far I have something along the lines:
Sub decimalPoint
dim Input As Integer
Console.WriteLine("Welcome")
Console.WriteLine("Enter amount of decimal place you wish to save to 1-5", 1-6) 'max 5dp.
input = Console.ReadLine()
End Sub
''Now I could do something like Console.WriteLine(Round(Convert.ToDecimal(input), 2)), but that's only based on whatever they input and not related to other functions/subs that I need it for. Any idea how I can link this to other subs?
notes:
It's a program with a menu.
Update: I got something along these lines now, but it's still not working.
Module Module1
Public Property MyResult As ...
Public Property MyDecimalInput As ...
Sub QuadraticFunction()
....Calculations
Console.WriteLine("Chose a decimal input: 1-5")
If ... = ... Then
Call decimalPoint()
MyResult = (....)
End Sub
Sub decimalPoint()
If MyDecimalInput = ...
Math.Round(MyResult) ...
...
End Sub
End Module
I don't know if this is what you're looking for but this is how I interpreted your question, but does this answer your question? If not let me know and I'll do my best to help :)
'converts text in textbox to integer
Dim decimalPoint As Integer = Convert.ToInt64(addTB.Text)
'stores newly rounded function into a number of user specified decimal places
Dim answer As Double = Math.Round(13.17435, decimalPoint)
'displays rounded answer
MsgBox(answer)
I want my program to take a variable, and find letters A-Z. I have made this section of my program in a module to be shared between 2 different forms.
variables are passed from form1 and are processed by the module and then sent back again to form1. the problem is I think some sort of bug in the code but I cant identify it.
Public Function UPCASES(ByRef password1, points) As Boolean
Dim intersection As IEnumerable(Of Char)
intersection = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".Intersect(password1)
'System.StackOverflowException error ^^^^^^^^^^^^^^^^^^^^^^^^^
If intersection.Count() = 1 Then
points = 5
Else
points = 0
End If
Return UPCASES(password1, points)
End Function
You are calling the method itself at the method end, that causes the StackOverflowException:
Return UPCASES(password1, points)
I guess this method should check if the password contains uppercase letters, then use:
Dim containsUpperCase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".Intersect(password1).Any()
So no need to create a method just for this one-liner, if you need a method:
Public Function ContainsUpperCaseLetter(password1 As String) As Boolean
Return "ABCDEFGHIJKLMNOPQRSTUVWXYZ".Intersect(password1).Any()
End Function
Side-note: you should change your default project settings to use Option Strict ON(Off is default unfortunately). Then you will be able to write much more safe, robust and performant code after you have learned a lot about .NET types because you have to fix the compiler errors.
This code doesn't seem to be working. I don't really know what loop to use to get it too add the information the user puts into the machine to print again.
The aim of this is for the user to either pick:
to print a menu that they have typed in an earlier database. If they haven't typed anything into the database, then it should be blank
Should let the user enter information into the database (What I am mostly struggling with) and do error checking so that it tells them if they have entered a number when they should have entered a letter and
To end the program.
When I do (2) It lets me type but it doesn't recall the information back in the database. Also it needs a number (4) which should return to the main menu. I think this is where the loops come in but I don't know which one to use.
Here is the code:
Structure Cars
Public carmake As String
Public carmodel As String
Public caryear As Integer
Public carlicence As String
End Structure
Module Module1
Sub Main()
Dim userchoice
Console.WriteLine("Choose weather to open the database(1), print it (2) or end (3)")
userchoice = Console.ReadLine()
If userchoice = 1 Then
Dim cardatabase(4) As Cars
Console.WriteLine("This will allow you to view the database.")
Console.WriteLine("Please enter the car make,licence,model and year")
cardatabase(1).carmake = Console.ReadLine()
cardatabase(1).carlicence = Console.ReadLine()
cardatabase(1).carmodel = Console.ReadLine()
cardatabase(1).caryear = Console.ReadLine()
ElseIf userchoice = 2 Then
Console.WriteLine("The database is,")
ElseIf userchoice = 3 Then
Console.WriteLine("Thanks for using this program.")
End If
Console.ReadLine()
End Sub
End Module
You have several issue with this code. Here's what I would recommend:
You need some sort of looping structure such as a While loop. Your test condition could be the userchoice variable.
In your If statements, you need to check if userchoice is equal to a string value instead of an integer value. So the line If userchoice = 1 Then should actually be If userchoice = "1" Then.
The cardatabase array should be declared outside of the loop. When you declare it in the loop, it will keep re-creating the array instead of adding more items to it.
Your Cars structure needs to be inside the Module Module1 block.
Since you don't know how many times the user may want to add a new car before they quit, I'd recommend using a List instead of an Array. Lists allow for easy dynamic re-sizing.
You need an integer variable to track the number of cars entered and use this as an index for your cardatabase collection.
Array/List indexes start with 0.
Cars should probably be a class instead of a structure. Also, it should be named Car. It's a single structure (or class, if you change it). The array itself should be called cars as it is a collection of a multiple Car structures (or objects if you change it to a class).
I was going to write example code here to demonstrate my points but it would be nearly an entire re-write and this would not help you understand why I made the changes I did.
My best advice to you is to go back through your book or tutorials that you read previously to get to this point and really try to understand what they are saying. If you don't get the concept, look it up elsewhere until you do.
Disclaimer: My recommendations are not comprehensive. I stopped examining your code when I identified all of the above issues right off the bat.
I'm creating a text based adventure game and would like to create some "global" commands & answers that would work anywhere no matter where your are.
For the global answers if we look at this code:
Module Module1
Private Property answer1 As String
Private Property answer2 As String
Sub Main()
Console.WriteLine("Welocome to the training grounds!")
Console.WriteLine("What would you like to do? 1. I would like to train on dummies")
answer1 = Console.ReadLine()
Console.WriteLine()
If answer1 = "1" Then
Console.WriteLine("Okay what now?")
answer2 = Console.ReadLine
If anwser2 = "1" Then Console.WriteLine("New option")
End If
End Sub
Now as you can see I have to create a string for each new user input. I've tried doing a Public answer As String = Console.ReadLineand then having things react to "answer" but if I reused a keyword like number 1 in the code up top the program would not wait for user input and just go down the path of number 1. The first option seems like a bunch of spagettih code and the second option dose not seem to work or I myself am not getting it to work so any tips here would be nice.
I also want to know if its possible to create a global string or something of sorts. Say that No matter if I were at the point where I'm supposed to give input to answer 1 or 2, if I typed in "inventory" it would open another sub called inventory. Now if possible I want to do this without having to have an if answer = inventory then Inventory().
Thanks in advance everyone ^^
Following the advice given to my by b.pell I was able to create a "GameCommand" sub but I'm not facing a problem of how to implement these into the game itself/make them accessible without ruining the game flow. I am also not quite sure how to write a command that will modify something in GameCommand.vb (say if the player gets an item how would I add it to the inventory list?)
Module Module1
Sub Main()
Dim gc As New GameCommand
If Console.ReadLine = "Go to dummy" Then Dummy() Else
CallByName(gc, Console.ReadLine, CallType.Method, "")
End Sub
Sub Dummy()
Console.WriteLine("I am dummy hear me roar")
Return
End Sub
End Module
The GameCommand.vb file is the same as the one in p.bells comment.
You could create an interpreter function that processes all commands and then do what you want in there. So everytime you read input in, just pass it along to the interpreter sub.
interpreter("inventory")
Inside of there, you could do an break that command up (if it has arguments). You could do a basic if statement and execute your sub procedures based off of that.
You could go above and beyond (this answers your question about not having to write the if's) and create a commands class that has all of your command methods on it (Inventory, North, South, East, West, Look) and then when a user enters a command you could use reflection to check that class to see if that sub/function exists (and then invoke it). The benefit of that is, as you add methods to the command class you never have to update the if logic in your interpreter again.
E.g. You would add a "Public Sub Look()" or "Public Sub Look(args as String) to the command class.. your interpreter would then try to invoke the look command (and maybe pass it the rest of the arguments). If it wasn't found, you tell the user it wasn't a command, if it was, it executes (google search for invoking). This means as you add Sub's the interpreter just picks them up.
Here is an MSDN article that should get you going, you can use VB's CallByName function, you pass it your class, then the proc name you want to execute with an args:
https://msdn.microsoft.com/en-us/library/chsc1tx6(v=vs.80).aspx
Here is a simple example (a console application):
Module1:
Module Module1
Sub Main()
Dim gc As New GameCommand
CallByName(gc, "Inventory", CallType.Method, "")
' Will look south
CallByName(gc, "Look", CallType.Method, "south")
' Will try to look southeast, but we don't accept that as a valid direction
CallByName(gc, "Look", CallType.Method, "southeast")
Console.ReadKey()
End Sub
End Module
GameCommand.vb:
Public Class GameCommand
Sub New()
End Sub
Public Shared Sub Inventory(arg As String)
Console.WriteLine("Execute code to show inventory")
End Sub
Public Shared Sub Look(direction As String)
If direction <> "north" And _
direction <> "south" And _
direction <> "east" And _
direction <> "west" Then
Console.WriteLine("Invalid direction")
Exit Sub
End If
Console.WriteLine("You look " & direction)
End Sub
End Class
I would approach a text adventure with the following general structure:
In your main module, loop through the process of each "turn".
Display any prompt text, as appropriate.
Read user input.
Check list of global commands and execute as appropriate.
Check list of local commands and execute as appropriate.
Display an error message.
Each command you execute should do the following:
Calculate changes to any variables affected by the command
Check each possible change in game status from the top down, and execute subsequent commands as appropriate. (E.G. Player death, mission success/failure, enemy defeated, etc.)
Advance the story to the appropriate place.
I'm writing a script that anonymizes participant data from a file.
Basically, I have:
A folder of plaintext participant data (sometimes CSV, sometimes XML, sometimes TXT)
A file of known usernames and accompanying anonymous IDs (e.g. jsmith1 as a known username, User123 as an anonymous ID)
I want to replace every instance of the known username with the corresponding anonymous ID.
Generally speaking, what I have works just fine -- it loads in the usernames and anonymous IDs into a dictionary and one by one runs a find-and-replace on the document text for each.
However, this script also strips out names, and it runs into some difficulty when it encounters names contained in other names. So, for example, I have two pairs:
John,User123
Johnny,User456
Now, when I run the find-and-replace, it may first encounter John, and as a result it replaces Johnny with User123ny, and then doesn't trigger Johnny.
The simplest solution I can think of is just to run the find-and-replace from longest key to shortest. To do that, it looks like I need a SortedDictionary.
However, I can't seem to convince Visual Basic to take my custom Comparer for this. How do you specify this? What I have is:
Sub Main()
Dim nameDict As New SortedDictionary(Of String, String)(AddressOf SortKeyByLength)
End Sub
Public Function SortKeyByLength(key1 As String, key2 As String) As Integer
If key1.Length > key2.Length Then
Return 1
ElseIf key1.Length < key2.Length Then
Return -1
Else
Return 0
End If
End Function
(The full details above are in case anyone has any better ideas for how to resolve this problem in general.)
I think it takes a class that implements the IComparer interface, so you'd want something like:
Public Class ByLengthComparer
Implements IComparer(Of String)
Public Function Compare(key1 As String, key2 As String) As Integer Implements IComparer(Of String).Compare
If key1.Length > key2.Length Then
Return 1
ElseIf key1.Length < key2.Length Then
Return -1
Else
'[edit: in response to comments below]
'Return 0
Return key1.Compare(key2)
End If
End Function
End Class
Then, inside your main method, you'd call it like this:
Dim nameDict As New SortedDictionary(Of String, String)(New ByLengthComparer())
You might want to take a look (or a relook) at the documentation for the SortedDictionary constructor, and how to make a class that implements IComparer.