Equivalent of fprintf's -20.15g formatting with C++ formatted streams ?

[Koen]

Hi,
could anyone please tell me how I can get the equivalent of this:
fprintf(aFile,"-20.15g",aDouble);
but in C++ using formatted streams?
I tried with C++ formatted streams using:
aStream.width(20);
aStream.precision(15);
but then if there's a very small value, scientific notation is not used
automatically and precision is lost (like in 0.000000000000003 instead
of 3.33333333333e-15).
I must be missing something here...
Koen

 

[Victor Bazarov]

could anyone please tell me how I can get the equivalent of this:
fprintf(aFile,"-20.15g",aDouble);
but in C++ using formatted streams?
I tried with C++ formatted streams using:
aStream.width(20);
aStream.precision(15);
but then if there's a very small value, scientific notation is not used
automatically and precision is lost (like in 0.000000000000003 instead
of 3.33333333333e-15).
I must be missing something here...

What book are you reading? All the manipulators are there for you to
use. See 'scientific' or 'fixed', see 'left' and 'right'... IOW RTFM

V