scientific computation

[Wing]

Hello eveyone,

I am programming some scientific computation based on C++. I would like
to set every output/input (e.g. cout, io file stream) to be a high
precision.

What C++ command should I use?

Thanks so much.

[Victor Bazarov]

Wing wrote:

I am programming some scientific computation based on C++. I would
like to set every output/input (e.g. cout, io file stream) to be a
high precision.

What C++ command should I use?

You need to read about 'setprecision', my guess would be.

V
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[Jacek Dziedzic]

Wing wrote:

Hello eveyone,

I am programming some scientific computation based on C++. I would like
to set every output/input (e.g. cout, io file stream) to be a high
precision.

What C++ command should I use?

First, #include<iomanip>.

Then choose fixed-point output (cout << fixed;)
or scientific-notation output (cout << scientific;).

Finally tell the output stream how many digits of precision
you require, eg. for 12 try

cout << setprecision(12);

That's basically it. For more details read up on "manipulators".

HTH,
- J.

[Marcus Kwok]

Jacek Dziedzic <jacek@no_spam.tygrys.no_spam.netwrote:

Wing wrote:

>Hello eveyone,

I am programming some scientific computation based on C++. I would like
to set every output/input (e.g. cout, io file stream) to be a high
precision.

What C++ command should I use?

First, #include<iomanip>.

Then choose fixed-point output (cout << fixed;)
or scientific-notation output (cout << scientific;).

Finally tell the output stream how many digits of precision
you require, eg. for 12 try

cout << setprecision(12);

That's basically it. For more details read up on "manipulators".

Also, the OP may want to investigate the use of
std::numeric_limits<T>::digits10 (requires #include <limits>), which
will give "the number of decimal digits that the type can represent
without change" (quote from Dinkumware documentation:
http://www.dinkumware.com/manuals/?m...its::digits10).

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Marcus Kwok
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