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Adding a function to a class

Posted on 2011-03-20
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Last Modified: 2012-05-11
I tried to add a tax function to a class and it seems like it is not working.  here is the function and class below.  Now in the code below, I get the following errors:

      Invalid token 'double' in class, struct, or interface member declaration

and

'MarketingEmail.ShoppingCart.CalculateTax(string)': not all code paths return a value

What could be causing these errors and how do I fix this so that there is no error.  I want to be able to do the code in class so that all I have to do is call the function in my program based on my class.  Thanks!
namespace MarketingEmail
{
    public class ShoppingCart
    {

        private int shoppingcartid;
        private int shoppingcartitemid;
        private int shoppingcartitemcount;
        

        
         function double CalculateTax(string CustomerState)
        {
            double salestax;

            switch(CustomerState)
            {
                   

                case "Alabama":
                    salestax = 4.0;
                    break;

                case "Alaska":
                    salestax = 0.0;
                    break;

                case "Arizona":
                    salestax = 6.6;
                    break;

                case "Arkansas":
                    salestax = 6.0;
                    break;

                case "California":
                    salestax = 8.25;
                    break;

                case "Colorado":
                    salestax = 2.9;
                    break;

                case "Connecticut":
                    goto case "Arkansas";

                case "Delaware":
                    goto case "Alaska";
                    
                case "District of Columbia":
                    goto case "Arkansas";

                case "Florida":
                    goto case "Arkansas";

                case "Georgia":
                    goto case "Alabama";                    

                case "Hawaii":
                    goto case "Alabama";

                case "Idaho":
                    goto case "Arkansas";

                case "Illinois":
                    salestax = 6.25;
                    break;

                case "Indiana":
                    salestax = 7.0;
                    break;

                case "Iowa":
                    goto case "Arkansas";

                case "Kansas":
                    salestax = 5.3;
                    break;

                case "Kentucky":
                    goto case "Arkansas";
                    
                case "Louisiana":
                    goto case "Alabama";

                case "Maine":
                    salestax = 5.0;
                    break;

                case "Maryland":
                    goto case "Arkansas";

                case "Massachusetts":
                    salestax = 6.25;
                    break;

                case "Michigan":
                    goto case "Arkansas";

                case "Minnesota":
                    salestax = 6.875;
                    break;

                case "Mississippi":
                    goto case "Indiana";

                case "Missouri":
                    salestax = 4.225;
                    break;

                case "Montana":
                    goto case "Alaska";

                case "Nebraska":
                    salestax = 7.7;
                    break;

                case "Nevada":
                    salestax = 6.85;
                    break;

                case "New Hampshire":
                    goto case "Alaska";

                case "New Jersey":
                    goto case "Indiana";

                case "New Mexico":
                    salestax = 5.125;
                    break;                    

                case "NJ":
                    salestax = 7.0;
                    break;
            }

            return salestax;
        }

    }
}

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0
Comment
Question by:VBBRett
5 Comments
 
LVL 11

Expert Comment

by:epichero22
ID: 35176490
What line is the first error on?
0
 
LVL 33

Accepted Solution

by:
Todd Gerbert earned 250 total points
ID: 35176560
Method's (or functions) in C# don't use the "Function" keyword, that's strictly a VB thing.

No:
function double CalculateTax(string CustomerState)
{
    ...
}

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Yes:
double CalculateTax(string CustomerState)
{
    ...
}

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Also, the C# compiler doesn't like it when you try and use a variable that never had anything assigned to it.
So, given:
double salestax;

switch(CustomerState)
{
    case "Alabama":
        salestax = 4.0;
        break;
}

return salestax;

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It's possible, if "CustomerState" doesn't match any of the "case" statements that salestax will never have anything assigned to it, so the compiler gives you an error.  You can solve that by assigning a value to salestax when you declare it:
double salestax = 0;

switch(CustomerState)
{
    case "Alabama":
        salestax = 4.0;
        break;
}

return salestax;

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Or by using a "default" case, which will be executed in the event no other case matches (which is probably a good idea anyway, will give you a chance to throw an exception or return a value indicating an error in case CustomerState isn't valid):
double salestax = 0;

switch(CustomerState)
{
	case "Alabama":
		salestax = 4.0;
		break;

    case "Alaska":
        salestax = 0.0;
        break;
	default:
		throw new Exception("Invalid CustomerState.");
}

return salestax;

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0
 
LVL 29

Assisted Solution

by:anarki_jimbel
anarki_jimbel earned 250 total points
ID: 35177033
What about the second error - you need some default case. Like tgerbert pointed out. But probably, you may not want to rise an exception if some wrong state string is passed. Some other options are possible.

E.g., you always return 0 if no such state.
Or, you return negative value (probably, not the nicest solution but some people do so).
3. Or, you may add some boolean out parameter, like 'out canGetTaxForState.

And so on.

I'd also initialize the return velue at the beginning of a function  - in C#, unlike VB, values are not initialized by default.
0
 

Author Comment

by:VBBRett
ID: 35177410
OK, it appears that the not all code paths return a value is line 21 and it is the following line of code:

double CalculateTax(string CustomerState)
0
 
LVL 33

Expert Comment

by:Todd Gerbert
ID: 35177455
I didn't get that error when I copy & paste your code, just the two matters I pointed out. Can you re post your code as it is now?
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