Sum with decimal types

[Alberto]

Actually I have two quantities (4.61) stored as decimal numbers.
Why if I try to sum them the result is 9.23 if the correct value is 9.22?

Thank you

[Chris Dunaway]

Are they stored as Decimal or as Single or Double?

When I use this code:

Dim s1, s2 As Decimal

s1 = 4.61D
s2 = 4.61D

MsgBox("Sum: " & (s1 + s2).ToString)

I get 9.22 as expected

[notifications]

Because if you use + there an implicit convertion where it rounds to the
nearest integer value. If you want to sum 2 decimals you should use the static
method "Add" which will undestand that you are dealing with decimal types.

System.Decimal d = System.Decimal.Add(4.61m, 4.61m);
result is 9.22

HTH,

Erick Sgarbi
www.blog.csharpbox.com

Actually I have two quantities (4.61) stored as decimal numbers. Why
if I try to sum them the result is 9.23 if the correct value is 9.22?

Thank you

[Jon Skeet [C# MVP]]

Alberto <al*****@nospam.com> wrote:

Actually I have two quantities (4.61) stored as decimal numbers.
Why if I try to sum them the result is 9.23 if the correct value is 9.22?

Do you mean actual decimals, or are they doubles? If they're doubles,
you should see
http://www.pobox.com/~skeet/csharp/floatingpoint.html

Otherwise, could you post a short but complete program which
demonstrates the problem?

See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Bob Grommes]

My first thought would be that both values are actually somewhere between
4.61 and 4.6149999. It may be that the numbers originated as doubles or
double constants and were explicitly converted to decimal someplace in your
code.

Be sure to use the "M" or "m" suffix for literal values being assigned to
decimal variables, e.g., 4.61M or 4.61m. Although supposedly there are no
implicit conversions in C# to the decimal type, 4.61 by itself will I
believe be interpreted as a double and then assigned to the decimal
variable, which may constitute an "explicit" conversion. I haven't checked,
but it wouldn't surprise me.

If you view the variables in the debugger, what numbers do you see in there?

--Bob

"Alberto" <al*****@nospam.com> wrote in message
news:%2******************@TK2MSFTNGP09.phx.gbl...

Actually I have two quantities (4.61) stored as decimal numbers.
Why if I try to sum them the result is 9.23 if the correct value is 9.22?

Thank you

[John B]

no***********@csharpbox.com wrote:

Because if you use + there an implicit convertion where it rounds to the
nearest integer value. Are you sure?
When I try

decimal d1 = 4.61m;
decimal d2 = 4.61m;
decimal d = d1 + d2;

it works as expected.
Of course if you were to try and add int and decimal it would but
decimal and decimal?

Cheers
JB
If you want to sum 2 decimals you should use the
static method "Add" which will undestand that you are dealing with
decimal types.

System.Decimal d = System.Decimal.Add(4.61m, 4.61m);
result is 9.22

HTH,

Erick Sgarbi
www.blog.csharpbox.com

Actually I have two quantities (4.61) stored as decimal numbers. Why
if I try to sum them the result is 9.23 if the correct value is 9.22?

Thank you

[Jon Skeet [C# MVP]]

<no***********@csharpbox.com> wrote:

Because if you use + there an implicit convertion where it rounds to the
nearest integer value.

No there isn't - not if either side is actually a decimal. If it were
rounding to the nearest *integer* value, the result wouldn't be 9.23,
would it?

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[notifications]

> My first thought would be that both values are actually somewhere

between 4.61 and 4.6149999. It may be that the numbers originated as
doubles or double constants and were explicitly converted to decimal
someplace in your code
My thoughts exactly...
HTH,

Erick Sgarbi
www.blog.csharpbox.com
My first thought would be that both values are actually somewhere
between 4.61 and 4.6149999. It may be that the numbers originated as
doubles or double constants and were explicitly converted to decimal
someplace in your code.

Be sure to use the "M" or "m" suffix for literal values being assigned
to decimal variables, e.g., 4.61M or 4.61m. Although supposedly there
are no implicit conversions in C# to the decimal type, 4.61 by itself
will I believe be interpreted as a double and then assigned to the
decimal variable, which may constitute an "explicit" conversion. I
haven't checked, but it wouldn't surprise me.

If you view the variables in the debugger, what numbers do you see in
there?

--Bob

"Alberto" <al*****@nospam.com> wrote in message
news:%2******************@TK2MSFTNGP09.phx.gbl...

Actually I have two quantities (4.61) stored as decimal numbers. Why
if I try to sum them the result is 9.23 if the correct value is 9.22?

Thank you