Formatting output of floating point numbers

[Martin]

Hi.

My question seems to be somewhat primitive, but I cannot find an
appropriate solution. Is it possible to control the number of digits
displayed in the exponent part of the scientific notation? I can use
'precision()' member function or 'setprecision' manipulator to control
the number of digits after the point:

cout.setf(ios_base::scientific, ios_base::floatfield);
cout.precision(8);
cout << 643.2963 << endl;

The result is 6.43296300e+002 with my stdlib. I want it to be printed
with 2 digits in exponent part, i.e. 02, not 002. How to achieve that?

Thanks in advance

Martin

[Victor Bazarov]

Martin wrote:

My question seems to be somewhat primitive, but I cannot find an
appropriate solution. Is it possible to control the number of digits
displayed in the exponent part of the scientific notation?

There is no easy standard way. Streams will output as many digits as
necessary and no more.

You can always write your own conversion routine which you can base on
stream conversion (say, to a string and then parsing that string).

I can use
'precision()' member function or 'setprecision' manipulator to control
the number of digits after the point:

cout.setf(ios_base::scientific, ios_base::floatfield);
cout.precision(8);
cout << 643.2963 << endl;

The result is 6.43296300e+002 with my stdlib. I want it to be printed
with 2 digits in exponent part, i.e. 02, not 002. How to achieve that?

By extracting the part after 'e' and shortening it.

V
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