Number

[ganeshmoorthy]

consider this calculation
Value 1 : 85200963741
Value 2 : 96300852147
Result : 8.20492541200395E+21
but the expected result should be 8204925412003949001927
I think it is converting the double value to something...
any help would be appreciated...
PS: All the variables are declared as double

[ThE_EnGinE]

The number is far too big. VB can only use numbers that are 18 digits long as the maximum, else it will go into what looks like standard form lol.

[ganeshmoorthy]

but windows calculator displays it correclty...

[ThE_EnGinE]

Windows calculator probably isn't made in VB.

[rnd me]

just sent calc to notepad, and it was made in C++.

can you add some zeros after the decimal?

vb's floating point is only so precise, does the difference matter to you? the discrepancy is tiny, percentage wise.

you might consider using a UDT to segment the calculations...

[ganeshmoorthy]

can you add some zeros after the decimal?

vb's floating point is only so precise, does the difference matter to you? the discrepancy is tiny, percentage wise.

could you explain it please...

[rnd me]

nevermind, i tried it.
you are apparantly stuck with "only" 16 digits of information

since multiplication is communitive, you could break the initial numbers into smaller components, mulitply those, convert them to a string, and combine them in a string representing the calc output...

like doing 5*5*5 instead of 25*5...

remember, 16 digits of info max...

[rnd me]

you might be able to use shell, and an outside command line calculator.
i also know that win2k/xp's SET command allow math operations, though i have no idea of what size limit is imposed. you can retrieve data from a set command using environ$.

[ganeshmoorthy]

thanks a lot md me...i'm actually developing a calculator project, i think the outside command line calculator or shell can be used... any example will be useful...

[tommygrayson]

consider this calculation
Value 1 : 85200963741
Value 2 : 96300852147
Result : 8.20492541200395E+21
but the expected result should be 8204925412003949001927
I think it is converting the double value to something...
any help would be appreciated...
PS: All the variables are declared as double

Why should you use double variables when a string can contain 255 digits.

[ganeshmoorthy]

so, what should be used...

[r0ach]

String mathematics is an ugly beast. I've written functions to do basic (+, -, *, /) on strings, but it's nasty.

The result displayed by the double is correct. All calculations done on it will be accurate. What you get is just the notation for huge numbers.

[tommygrayson]

so, what should be used...

If you have declared it as String you may try this.

StrTotal = FormatNumber(CDbl(Value 1) + CDbl(Value 2), 22)

Maybe it will work.

[rnd me]

ok, well i checked, and SET is out, at least for this.
just for reference:
C:\>set /a Result = "85200963741 * 96300852147"
but it returns:
Invalid number. Numbers are limited to 32-bits of precision.

perhaps running a java script on an IE form would do the trick...

[r0ach]

By the way, the string notation calculates as (using example above):


8.20492541200395 * (10 ^ 21)

[ganeshmoorthy]

If you have declared it as String you may try this.

StrTotal = FormatNumber(CDbl(Value 1) + CDbl(Value 2), 22)

for you kind information, please read my post clearly, I already declared the variables as double...

The result displayed by the double is correct. All calculations done on it will be accurate. What you get is just the notation for huge numbers.

Yes, I know that...but I want to disply the result in normal numbers not in notations....

[r0ach]

Here, this works:

Dim a As Double
  Dim b As Double
  Dim c As Double
  
  a = 85200963741#
  b = 96300852147#
  c = a * b
  
  'displays: 8,204,925,412,003,950,000,000.00
  Debug.Print Format(c, "#,##0.00")

I think it's as accurate as you'll get it with normal vb functions

[ganeshmoorthy]

r0ach : If I use the post #17, then
I get
7259204222395200000000.00
instead of
7259204222395196715081
for the calculation 85200963741 * 85200963741
do you think is that ok...
even for the values you have given, the actual result in windows calculator is 8204925412003949001927, but your code will return 8,204,925,412,003,950,000,000.00

[tommygrayson]

for you kind information, please read my post clearly, I already declared the variables as double...


Yes, I know that...but I want to disply the result in normal numbers not in notations....

Perhaps, you did not understood me.

If you declared your total number to string then the above expression would be appropriate.

You did not say that you would only want to use double variables only.

[r0ach]

You can specify "###" or 22 like tommygrayson mentioned, but I googled and it appears as though VB is limited to 15 significant digits.

Even MS Excel 2003 gives 7259204222395200000000.00 instead of 7259204222395196715081