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Simple math is giving me trouble

P: n/a
I am trying to add dollar amounts together and add sales tax but everthing
after the decimal point is being cut off in the dollar amounts. Here is my
code:

if (Adults != "")
{
AdultTotal = int.Parse(Adults) * Convert.ToInt32(myReader["RateAdult"]);

ttlAdults.Text = Adults;
}

if (Children != "")
{
ChildTotal = int.Parse(Children) * Convert.ToInt32(myReader["RateChild"]);

ttlChildren.Text = Children;
}

double Tax = (AdultTotal + ChildTotal ) * (.06);
double TotalCost = (AdultTotal + ChildTotal );

txtTotal.Text = TotalCost.ToString() + " " + Tax.ToString();

The Adults and Children variables are ints and contain a quantity amount
from a form. The rate is grabbed from the database this is where the problem
is everything after the decimal in the rates are being chopped off.

I know I am probably using the wrong types. What is correct way to do this?

Thank you very much, Justin.
Nov 18 '05 #1
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6 Replies


P: n/a
I don't really understand your question... when you speak of rates you mean
the tax?
anyway, double is good for numerical simulation but bad for accounting
I would advice you to use the decimal type
"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:73**********************************@microsof t.com...
I am trying to add dollar amounts together and add sales tax but everthing
after the decimal point is being cut off in the dollar amounts. Here is my
code:

if (Adults != "")
{
AdultTotal = int.Parse(Adults) * Convert.ToInt32(myReader["RateAdult"]);

ttlAdults.Text = Adults;
}

if (Children != "")
{
ChildTotal = int.Parse(Children) * Convert.ToInt32(myReader["RateChild"]);

ttlChildren.Text = Children;
}

double Tax = (AdultTotal + ChildTotal ) * (.06);
double TotalCost = (AdultTotal + ChildTotal );

txtTotal.Text = TotalCost.ToString() + " " + Tax.ToString();

The Adults and Children variables are ints and contain a quantity amount
from a form. The rate is grabbed from the database this is where the
problem
is everything after the decimal in the rates are being chopped off.

I know I am probably using the wrong types. What is correct way to do
this?

Thank you very much, Justin.

Nov 18 '05 #2

P: n/a
Int's don't carry any information beyond the decimal place. You could use
doubles or floats. Also you should add your Tax into the TotalCost to come
up with the GrandTotal.
"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:73**********************************@microsof t.com...
I am trying to add dollar amounts together and add sales tax but everthing
after the decimal point is being cut off in the dollar amounts. Here is my
code:

if (Adults != "")
{
AdultTotal = int.Parse(Adults) * Convert.ToInt32(myReader["RateAdult"]);

ttlAdults.Text = Adults;
}

if (Children != "")
{
ChildTotal = int.Parse(Children) * Convert.ToInt32(myReader["RateChild"]);

ttlChildren.Text = Children;
}

double Tax = (AdultTotal + ChildTotal ) * (.06);
double TotalCost = (AdultTotal + ChildTotal );

txtTotal.Text = TotalCost.ToString() + " " + Tax.ToString();

The Adults and Children variables are ints and contain a quantity amount
from a form. The rate is grabbed from the database this is where the problem is everything after the decimal in the rates are being chopped off.

I know I am probably using the wrong types. What is correct way to do this?
Thank you very much, Justin.

Nov 18 '05 #3

P: n/a
I have tried using decimal, double and float but I get an error when I try to
multiply using these types, it wants to convert the numbers to ints. Heres
the new code:

int Adults = int.Parse(Request.Cookies["qntyAdult"].Value);
decimal PriceAdult = Convert.ToDecimal(myReader["RateAdult"]);

AdultTotal = Convert.ToDecimal(Adults) *
Convert.ToDecimal(myReader["RateAdult"]);

I can't believe something so simple has turned out to be difficult,
ahhhhhhh!!!!!!!

"ESPN Lover" wrote:
Int's don't carry any information beyond the decimal place. You could use
doubles or floats. Also you should add your Tax into the TotalCost to come
up with the GrandTotal.
"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:73**********************************@microsof t.com...
I am trying to add dollar amounts together and add sales tax but everthing
after the decimal point is being cut off in the dollar amounts. Here is my
code:

if (Adults != "")
{
AdultTotal = int.Parse(Adults) * Convert.ToInt32(myReader["RateAdult"]);

ttlAdults.Text = Adults;
}

if (Children != "")
{
ChildTotal = int.Parse(Children) * Convert.ToInt32(myReader["RateChild"]);

ttlChildren.Text = Children;
}

double Tax = (AdultTotal + ChildTotal ) * (.06);
double TotalCost = (AdultTotal + ChildTotal );

txtTotal.Text = TotalCost.ToString() + " " + Tax.ToString();

The Adults and Children variables are ints and contain a quantity amount
from a form. The rate is grabbed from the database this is where the

problem
is everything after the decimal in the rates are being chopped off.

I know I am probably using the wrong types. What is correct way to do

this?

Thank you very much, Justin.


Nov 18 '05 #4

P: n/a
Hi Justin,

When using C#, it isn't necessary to use the Convert class to convert
integers to other numeric data types. Most of them can be implicitly cast.
Example:

int Adults = int.Parse(Request.Cookies["qntyAdult"].Value);
double PriceAdult = Convert.ToDouble(myReader["RateAdult"]);
double AdultTotal = ((double) Adults) * Adult;

ttlAdults.Text = Adults.ToString();

.... // Same for Children

double Tax = (AdultTotal + ChildTotal) * 0.06d; // Shouldn't need the "d"
but it's a good example
double TotalCost = AdultTotal + ChildTotal; // Same data type, no
casting necessary

txtTotal.Text = TotalCost.ToString("0.00") + " " + Tax.ToString("0.00");

Note the use of the formatting strings in the final statement. If you want 2
decimal places in the final string, you need to specify that there. Also,
mixing up the use of Decimal and Double isn't necessary or good. A Double
can hold a lot more precision than a decimal, so if you have doubts, use all
doubles. In any case, use all somethings (decimals, doubles, whatever floats
your boat), to make life (and your code) much simpler.

--
HTH,
Kevin Spencer
..Net Developer
Microsoft MVP
I get paid good money to
solve puzzles for a living

"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:B2**********************************@microsof t.com...
I have tried using decimal, double and float but I get an error when I try to multiply using these types, it wants to convert the numbers to ints. Heres
the new code:

int Adults = int.Parse(Request.Cookies["qntyAdult"].Value);
decimal PriceAdult = Convert.ToDecimal(myReader["RateAdult"]);

AdultTotal = Convert.ToDecimal(Adults) *
Convert.ToDecimal(myReader["RateAdult"]);

I can't believe something so simple has turned out to be difficult,
ahhhhhhh!!!!!!!

"ESPN Lover" wrote:
Int's don't carry any information beyond the decimal place. You could use doubles or floats. Also you should add your Tax into the TotalCost to come up with the GrandTotal.
"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:73**********************************@microsof t.com...
I am trying to add dollar amounts together and add sales tax but everthing after the decimal point is being cut off in the dollar amounts. Here is my code:

if (Adults != "")
{
AdultTotal = int.Parse(Adults) * Convert.ToInt32(myReader["RateAdult"]);
ttlAdults.Text = Adults;
}

if (Children != "")
{
ChildTotal = int.Parse(Children) * Convert.ToInt32(myReader["RateChild"]);
ttlChildren.Text = Children;
}

double Tax = (AdultTotal + ChildTotal ) * (.06);
double TotalCost = (AdultTotal + ChildTotal );

txtTotal.Text = TotalCost.ToString() + " " + Tax.ToString();

The Adults and Children variables are ints and contain a quantity amount from a form. The rate is grabbed from the database this is where the

problem
is everything after the decimal in the rates are being chopped off.

I know I am probably using the wrong types. What is correct way to do

this?

Thank you very much, Justin.


Nov 18 '05 #5

P: n/a
Thank you very much!

For the sake of learning what the (double) do in ((double) Adults)?

Thanks, Justin.

"Kevin Spencer" wrote:
Hi Justin,

When using C#, it isn't necessary to use the Convert class to convert
integers to other numeric data types. Most of them can be implicitly cast.
Example:

int Adults = int.Parse(Request.Cookies["qntyAdult"].Value);
double PriceAdult = Convert.ToDouble(myReader["RateAdult"]);
double AdultTotal = ((double) Adults) * Adult;

ttlAdults.Text = Adults.ToString();

.... // Same for Children

double Tax = (AdultTotal + ChildTotal) * 0.06d; // Shouldn't need the "d"
but it's a good example
double TotalCost = AdultTotal + ChildTotal; // Same data type, no
casting necessary

txtTotal.Text = TotalCost.ToString("0.00") + " " + Tax.ToString("0.00");

Note the use of the formatting strings in the final statement. If you want 2
decimal places in the final string, you need to specify that there. Also,
mixing up the use of Decimal and Double isn't necessary or good. A Double
can hold a lot more precision than a decimal, so if you have doubts, use all
doubles. In any case, use all somethings (decimals, doubles, whatever floats
your boat), to make life (and your code) much simpler.

--
HTH,
Kevin Spencer
..Net Developer
Microsoft MVP
I get paid good money to
solve puzzles for a living

"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:B2**********************************@microsof t.com...
I have tried using decimal, double and float but I get an error when I try

to
multiply using these types, it wants to convert the numbers to ints. Heres
the new code:

int Adults = int.Parse(Request.Cookies["qntyAdult"].Value);
decimal PriceAdult = Convert.ToDecimal(myReader["RateAdult"]);

AdultTotal = Convert.ToDecimal(Adults) *
Convert.ToDecimal(myReader["RateAdult"]);

I can't believe something so simple has turned out to be difficult,
ahhhhhhh!!!!!!!

"ESPN Lover" wrote:
Int's don't carry any information beyond the decimal place. You could use doubles or floats. Also you should add your Tax into the TotalCost to come up with the GrandTotal.
"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:73**********************************@microsof t.com...
> I am trying to add dollar amounts together and add sales tax but everthing > after the decimal point is being cut off in the dollar amounts. Here is my > code:
>
> if (Adults != "")
> {
> AdultTotal = int.Parse(Adults) * Convert.ToInt32(myReader["RateAdult"]); >
> ttlAdults.Text = Adults;
> }
>
> if (Children != "")
> {
> ChildTotal = int.Parse(Children) * Convert.ToInt32(myReader["RateChild"]); >
> ttlChildren.Text = Children;
> }
>
> double Tax = (AdultTotal + ChildTotal ) * (.06);
> double TotalCost = (AdultTotal + ChildTotal );
>
> txtTotal.Text = TotalCost.ToString() + " " + Tax.ToString();
>
> The Adults and Children variables are ints and contain a quantity amount > from a form. The rate is grabbed from the database this is where the
problem
> is everything after the decimal in the rates are being chopped off.
>
> I know I am probably using the wrong types. What is correct way to do
this?
>
> Thank you very much, Justin.


Nov 18 '05 #6

P: n/a
> For the sake of learning what the (double) do in ((double) Adults)?

It's a C# cast. Since Adults is an integer, it casts it as a double, which
is fine, as a double is larger in memory and more precise than an integer.

The rules for doing math can be kind of tricky. While you can often do math
on some different numeric data types without casting, the data type of the
result may or may not be the type you expect. It's therefore a good practice
to explicitly cast all operands to the same data type (the one you need for
a result) prior to operating on them.

--
HTH,
Kevin Spencer
..Net Developer
Microsoft MVP
I get paid good money to
solve puzzles for a living

"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:A9**********************************@microsof t.com...
Thank you very much!

For the sake of learning what the (double) do in ((double) Adults)?

Thanks, Justin.

"Kevin Spencer" wrote:
Hi Justin,

When using C#, it isn't necessary to use the Convert class to convert
integers to other numeric data types. Most of them can be implicitly cast. Example:

int Adults = int.Parse(Request.Cookies["qntyAdult"].Value);
double PriceAdult = Convert.ToDouble(myReader["RateAdult"]);
double AdultTotal = ((double) Adults) * Adult;

ttlAdults.Text = Adults.ToString();

.... // Same for Children

double Tax = (AdultTotal + ChildTotal) * 0.06d; // Shouldn't need the "d" but it's a good example
double TotalCost = AdultTotal + ChildTotal; // Same data type, no
casting necessary

txtTotal.Text = TotalCost.ToString("0.00") + " " + Tax.ToString("0.00");

Note the use of the formatting strings in the final statement. If you want 2 decimal places in the final string, you need to specify that there. Also, mixing up the use of Decimal and Double isn't necessary or good. A Double can hold a lot more precision than a decimal, so if you have doubts, use all doubles. In any case, use all somethings (decimals, doubles, whatever floats your boat), to make life (and your code) much simpler.

--
HTH,
Kevin Spencer
..Net Developer
Microsoft MVP
I get paid good money to
solve puzzles for a living

"Justin" <Ju****@discussions.microsoft.com> wrote in message
news:B2**********************************@microsof t.com...
I have tried using decimal, double and float but I get an error when I try
to
multiply using these types, it wants to convert the numbers to ints.
Heres the new code:

int Adults = int.Parse(Request.Cookies["qntyAdult"].Value);
decimal PriceAdult = Convert.ToDecimal(myReader["RateAdult"]);

AdultTotal = Convert.ToDecimal(Adults) *
Convert.ToDecimal(myReader["RateAdult"]);

I can't believe something so simple has turned out to be difficult,
ahhhhhhh!!!!!!!

"ESPN Lover" wrote:

> Int's don't carry any information beyond the decimal place. You could use
> doubles or floats. Also you should add your Tax into the TotalCost
to come
> up with the GrandTotal.
>
>
> "Justin" <Ju****@discussions.microsoft.com> wrote in message
> news:73**********************************@microsof t.com...
> > I am trying to add dollar amounts together and add sales tax but

everthing
> > after the decimal point is being cut off in the dollar amounts.
Here is my
> > code:
> >
> > if (Adults != "")
> > {
> > AdultTotal = int.Parse(Adults) *

Convert.ToInt32(myReader["RateAdult"]);
> >
> > ttlAdults.Text = Adults;
> > }
> >
> > if (Children != "")
> > {
> > ChildTotal = int.Parse(Children) *

Convert.ToInt32(myReader["RateChild"]);
> >
> > ttlChildren.Text = Children;
> > }
> >
> > double Tax = (AdultTotal + ChildTotal ) * (.06);
> > double TotalCost = (AdultTotal + ChildTotal );
> >
> > txtTotal.Text = TotalCost.ToString() + " " + Tax.ToString();
> >
> > The Adults and Children variables are ints and contain a quantity

amount
> > from a form. The rate is grabbed from the database this is where

the > problem
> > is everything after the decimal in the rates are being chopped off. > >
> > I know I am probably using the wrong types. What is correct way to do > this?
> >
> > Thank you very much, Justin.
>
>
>


Nov 18 '05 #7

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