CODEWITHSUNDEEP
vb.netvisual-studio-2010
DumbQuesionGuy314
DumbQuesionGuy314

Reputation: 173

Basic Visual Basic Program Error - Probably Variable Error

I am writing this program for visual basic that will determine a bill based off water usage. My problem is that all values I input come back as zero in the command prompt. Can anyone explain what's wrong with this code? 

Option Explicit On
Option Strict On

Imports System

module eurekawatercompany

  Sub Main ()
    ' Declare variables of problem
    Dim waterusage as double 
    Dim totalcharge as double

    ' Prompts for user to enter their water usage.
    Console.write ("Please enter your current water usage (cubic feet): ")
    waterusage = convert.toint32(console.readline())
      If (waterusage < 1000) then
      totalcharge = 15

      End If

      If (1000 > waterusage) and (waterusage < 2000) then
      totalcharge = 0.0175 * waterusage + 15

      End If

      else if (2000 < waterusage) and (waterusage > 3000) then
      totalcharge = 0.02 * waterusage + 32.5

      End If
      ' 32.5 is the price of exactly 2000cm^(3) of water

      else if (waterusage > 3000) then
      totalcharge = 70

      End If

    Console.out.writeline ("Total charge is: ")
      Console.out.writeline (totalcharge)


  End sub

End Module

Upvotes: 1

Views: 561

Answers (1)

paxdiablo
paxdiablo

Reputation: 881113

First up, your statement:

If (1000 > waterusage) and (waterusage < 2000) then

is equivalent to:

If (waterusage < 1000) and (waterusage < 2000) then

meaning that it's testing that waterusage is both less than 1000 and less than 2000 (ie, just that it's less than 1000). I think you may have meant something along the lines of:

If (waterusage > 1000) and (waterusage <= 2000) then

You'll notice I've used <= as well since your if statements don't handle the edge cases at all (2000 is neither less than, nor greater than, 2000 so entering 2000 would cause none of your original if statements to fire).

You'll also need to make similar changes to the 0 to 1000 and 2000 to 3000 cases.

I'm also not entirely certain that the:

:
End If
else if ...

construct is correct (unless VB.NET has changed drastically at the lower levels since the VB6 days (I know that there were a lot of changes but changing such a low-level thing as the workings of if would be unlikely). An end if closes off the entire if statement as far as I'm aware, so the else should be between the if and end if.

So I'd be looking at something like:

Option Explicit On
Option Strict On
Imports System
Module EurekaWaterCompany

Sub Main ()
    Dim WaterUsage as double
    Dim TotalCharge as double

    Console.Out.Write ("Please enter your current water usage (cubic feet): ")
    WaterUsage = Convert.ToInt32 (Console.In.ReadLine())

    If (WaterUsage <= 1000) then
        TotalCharge = 15
    ElseIf (WaterUsage > 1000) and (WaterUsage <= 2000) then
        TotalCharge = 0.0175 * WaterUsage + 15
    ElseIf (Waterusage > 2000) and (WaterUsage <= 3000) then
        TotalCharge = 0.02 * WaterUsage + 32.5
    Else
        TotalCharge = 70
    End If

    Console.Out.WriteLine ("Total charge is: ")
    Console.Out.WriteLine (TotalCharge)
End sub

End Module

That code also has some minor fixes like properly specifying Out and In for the I/O, and using "proper" capitalisation, although it's not fully tested and may still have some syntax errors. The idea behind the code (basically the if statement) is still sound.

However, you may want to check your specifications.

When utilities charge for their resource, they tend to levy higher rates on the excess beyond a certain level, not the entire amount. In other words, I'd expect to see a charge of $15 on the first 1000 cubic feet and then 1.75 cents on each cubic foot beyond that, which would make your statements look more like:

ElseIf (WaterUsage > 1000) and (WaterUsage <= 2000) then
    TotalCharge = 0.0175 * (WaterUsage - 1000) + 15

That would make sense in this situation since you'd be charged 1.5c/ft3 for the first thousand, 1.75c/ft3 for the second thousand, and 2c/ft3 for the third thousand, with a lower limit of $15 (you get charged for the first thousand no matter how much you actually use) and a fixed charge of $70 for anyone who uses more than three thousand cubic feet (sort of a penalty rate).

But, that's supposition on my part, from experience. It may be that your specifications say otherwise, in which case feel free to ignore this section.

Upvotes: 3

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