I,m developing a debt calculation program 'my problem is when i have to calculate the months to pay back the debt it comes to 28.04 and i have to get it to 29 can some one pls help me out.
Thank you in advance
my code looks like this:
Dim b, SubMtP As Integer
Dim outsUm, si
outsUm = TextBox1.Text
SubMtP = Format(Val(TextBox1.Text) / Val(TextBox2.Text), "0.00")
Math.Round(SubMtP + 1)
TextBox5.Text = Format(Val(TextBox4.Text) / 12, "0.00")
For i As Integer = 1 To SubMtP
Use Math.Ceiling.
As Pavel said in the comment, you need to assign the result, and you should use Ceiling:
Dim result As Double = Math.Ceiling(SubMtP)
You are also strongly encouraged to switch Option Strict On everywhere in your code to enable strict, static type checking. This will result in a few compile errors in your above code that will need to be cleaned up. This is good because these code fragments are potential errors in your code and make it hard to maintain and to understand.
The line
Math.Round(SubMtP + 1)
does not do anything (has no side effects) since you aren't assinging or otherwise using the result.
If you are trying to get from 28.04 to 29 then you probably want Math.Ceiling. It's hard to tell what you are trying to do, but you probably want
SubMtP = Math.Ceiling(SubMtP);
Related
I am trying to program a way to read a text file and match all the values and their quantites. For example if the text file is like this:
Bread-10 Flour-2 Orange-2 Bread-3
I want to create a list with the total quantity of all the common words. I began my code, but I am having trouble understanding to to sum the values. I'm not asking for anyone to write the code for me but I am having trouble finding resources. I have the following code:
Dim query = From data In IO.File.ReadAllLines("C:\User\Desktop\doc.txt")
Let name As String = data.Split("-")(0)
Let quantity As Integer = CInt(data.Split("-")(1))
Let sum As Integer = 0
For i As Integer = 0 To query.Count - 1
For j As Integer = i To
Next
Thanks
Ok, lets break this down. And I not seen the LET command used for a long time (back in the GWBASIC days!).
But, that's ok.
So, first up, we going to assume your text file is like this:
Bread-10
Flour-2
Orange-2
Bread-3
As opposed to this:
Bread-10 Flour-2 Orange-2 Bread-3
Now, we could read one line, and then process the information. Or we can read all lines of text, and THEN process the data. If the file is not huge (say a few 100 lines), then performance is not much of a issue, so lets just read in the whole file in one shot (and your code also had this idea).
Your start code is good. So, lets keep it (well ok, very close).
A few things:
We don't need the LET for assignment. While older BASIC languages had this, and vb.net still supports this? We don't need it. (but you will see examples of that still floating around in vb.net - especially for what we call "class" module code, or "custom classes". But again lets just leave that for another day.
Now the next part? We could start building up a array, look for the existing value, and then add it. However, this would require a few extra arrays, and a few extra loops.
However, in .net land, we have a cool thing called a dictionary.
And that's just a fancy term of for a collection VERY much like an array, but it has some extra "fancy" features. The fancy feature is that it allows one to put into the handly list things by a "key" name, and then pull that "value" out by the key.
This saves us a good number of extra looping type of code.
And it also means we don't need a array for the results.
This key system is ALSO very fast (behind the scene it uses some cool concepts - hash coding).
So, our code to do this would look like this:
Note I could have saved a few lines here or there - but that would make this code hard to read.
Given that you look to have Fortran, or older BASIC language experience, then lets try to keep the code style somewhat similar. it is stunning that vb.net seems to consume even 40 year old GWBASIC type of syntax here.
Do note that arrays() in vb.net do have some fancy "find" options, but the dictionary structure is even nicer. It also means we can often traverse the results with out say needing a for i = 1 to end of array, and having to pull out values that way.
We can use for each.
So this would work:
Dim MyData() As String ' an array() of strings - one line per array
MyData = File.ReadAllLines("c:\test5\doc.txt") ' read each line to array()
Dim colSums As New Dictionary(Of String, Integer) ' to hold our values and sum them
Dim sKey As String
Dim sValue As Integer
For Each strLine As String In MyData
sKey = Split(strLine, "-")(0)
sValue = Split(strLine, "-")(1)
If colSums.ContainsKey(sKey) Then
colSums(sKey) = colSums(sKey) + sValue
Else
colSums.Add(sKey, sValue)
End If
Next
' display results
Dim KeyPair As KeyValuePair(Of String, Integer)
For Each KeyPair In colSums
Debug.Print(KeyPair.Key & " = " & KeyPair.Value)
Next
The above results in this output in the debug window:
Bread = 13
Flour = 2
Orange = 2
I was tempted here to write this code using just pure array() in vb.net, as that would give you a good idea of the "older" types of coding and syntax we could use here, and a approach that harks all the way back to those older PC basic systems.
While the dictionary feature is more advanced, it is worth the learning curve here, and it makes this problem a lot easier. I mean, if this was for a longer list? Then I would start to consider introduction of some kind of data base system.
However, without some data system, then the dictionary feature is a welcome approach due to that "key" value lookup ability, and not having to loop. It also a very high speed system, so the result is not much looping code, and better yet we write less code.
Ok so I was in college and I was talking to my teacher and he said my code isn't good practice. I'm a bit confused as to why so here's the situation. We basically created a for loop however he declared his for loop counter outside of the loop because it's considered good practice (to him) even though we never used the variable later on in the code so to me it looks like a waste of memory. We did more to the code then just use a message box but the idea was to get each character from a string and do something with it. He also used the Mid() function to retrieve the character in the string while I called the variable with the index. Here's an example of how he would write his code:
Dim i As Integer = 0
Dim justastring As String = "test"
For i = 1 To justastring.Length Then
MsgBox( Mid( justastring, i, 1 ) )
End For
And here's an example of how I would write my code:
Dim justastring As String = "test"
For i = 0 To justastring.Length - 1 Then
MsgBox( justastring(i) )
End For
Would anyone be able to provide the advantages and disadvantages of each method and why and whether or not I should continue how I am?
Another approach would be, to just use a For Each on the string.
Like this no index variable is needed.
Dim justastring As String = "test"
For Each c As Char In justastring
MsgBox(c)
Next
I would suggest doing it your way, because you could have variables hanging around consuming(albeit a small amount) of memory, but more importantly, It is better practice to define objects with as little scope as possible. In your teacher's code, the variable i is still accessible when the loop is finished. There are occasions when this is desirable, but normally, if you're only using a variable in a limited amount of code, then you should only declare it within the smallest block that it is needed.
As for your question about the Mid function, individual characters as you know can be access simply by treating the string as an array of characters. After some basic benchmarking, using the Mid function takes a lot longer to process than just accessing the character by the index value. In relatively simple bits of code, this doesn't make much difference, but if you're doing it millions of times in a loop, it makes a huge difference.
There are other factors to consider. Such as code readability and modification of the code, but there are plenty of websites dealing with that sort of thing.
Finally I would suggest changing some compiler options in your visual studio
Option Strict to On
Option Infer to Off
Option Explicit to On
It means writing more code, but the code is safer and you'll make less mistakes. Have a look here for an explanation
In your code, it would mean that you have to write
Dim justastring As String = "test"
For i As Integer = 0 To justastring.Length - 1 Then
MsgBox( justastring(i) )
End For
This way, you know that i is definitely an integer. Consider the following ..
Dim i
Have you any idea what type it is? Me neither.
The compiler doesn't know what so it defines it as an object type which could hold anything. a string, an integer, a list..
Consider this code.
Dim i
Dim x
x = "ab"
For i = x To endcount - 1
t = Mid(s, 999)
Next
The compiler will compile it, but when it is executed you'll get an SystemArgumenException. In this case it's easy to see what is wrong, but often it isn't. And numbers in strings can be a whole new can of worms.
Hope this helps.
I made a program that generates a daily index code.
It gets created from
Employer (everyone has a number from 0-9)
Date of serial code requested
Everything is working fine, but I wannt to remove the dots from the date
I tried things like
date.Text = date.Text.Replace(".""", """")
or
Dim clean as String
clean = myString.Replace(".", "")
But nothing happens
May be I just didnt unterstand the using... If yes, so please help me to find a alternative.
Ok i will try to explain better.
As I lunch it a textbox gets the date of today, the textbox is called date
Ive got a combobox, from there you select the employer. Every employer has a number. For example Andreas is Number 1.
I wannt to do something like:
if combobox1.text = "Andreas" then
dailyCode.text = "1" & date.text
end if
My problem is that the date is written with dots, the daily code should not have dots.
Sorry for my bad English
In your questions Details are still incomplete.still assuming that the date(still i am confused how are you using reserved keyword) is declared as date type itself,consider formatting it with Format function itself.
Try using
Dim s As String = Format(date, "ddMMMyyyy")
hope that helps.
Is it possible to convert, say, a textbox input to working code?
For example, user types 'if x<10 then y=2 else y=5' into textbox1, it gets used directly as code something like ...
dim x as integer = 5
dim y as integer = 0
include processed textbox1.text
resultbox.text = (y*20).tostring
It's not important why this would be needed - just whether there is any straight-forward method that parses a string to code.
Many thanks.
Maybe this is what you are looking for:
http://www.codeproject.com/Articles/12852/Compile-and-Run-VB-NET-Code-using-the-CodeDom
yes you can do this using the VBCodeProvider class. Although the amount of code required is quite significant:
http://www.codeproject.com/Articles/5472/Compiling-NET-code-on-the-fly
If I have a string like input = "AA["
If Right(input, 1) = "[" Then Do stuff
The If statement returns false, even if I try converting things around to chars, etc etc. But if I do this is returns true:
Dim temp As String = Right(input, 1)
If temp = "[" Then Do Stuff
I like knowing little semantics like this, any idea why it comes out this way?
Or don't use Right at all since this is .Net
Dim s As String = "AAAAAAA]"
If s.Substring(s.Length - 1, 1) = "]" Then
Stop
End If
'or
If s(s.Length - 1) = "]" Then
Stop
End If
I've seen weird behavior like that when debugging.
In fact, today I had something simlar
Dim records As Integer
records = If(o.dr Is Nothing, o.ADO.rs.RecordCount, o.ADO.DS.Tables("tbl").Rows.Count)
That should work, using the rs.RecordCount when dr is nothing, otherwise using the Rows.Count. It didn't, records was ending up as zero. Rewrote it as a full if then/else block and it works.
It's never my first thought that the compiler/debugger/ide is messing things up, but you should keep it in the back of your mind for consideration: the programmers that wrote those programs are just as human and fallible as you or me.
It shouldn't. Are you sure you didn't have a typo? The result of RIGHT is a string, and if the input was truly "AA[" the IF will have passed.
I've never had VB act wonky on something like this.
If the code appears in a form, then the .Right property of the form overrides the string manipulation function. You need to specify the parent namespace - e.g. VisualBasic.Right - to ensure that you get the correct method.
I think you may have some kind of strange overload confusion occuring here.
You are specifiing "Right" (which could be calling a local "Right" function).
The function your implying is "Microsoft.VisualBasic.Strings.Right" in most of my code ends up being "Strings.Right" due to the global import.
I would try changing you code to the below and see if it still happens, in order to rule out some overload/scope confusion. (and/or the reduced "Strings.Right")
If Micosoft.VisualBasic.Strings.Right(input, 1) = "[" Then Do stuff