Question

How to convert a Double precision number into a string but showing only two decimal places in C++

Asked by: Giampete

Am trying to print a number showing only two decimal places ;  this is after
calculating in double precision then converting the number into a string.

I need to do something in between I think... would appreciate some help have also attached the code

fastcall TForm3::TForm3(TComponent* Owner)
	: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm3::SpeedButton1Click(TObject *Sender)
{
double  m,dd,c,d,db,f,fc,asr,b,as_min;
 
 m=Umoment->Text.ToDouble();
 dd=Ddepth->Text.ToDouble();
 c=Co->Text.ToDouble();
 db=d_bar->Text.ToDouble();
 f=fy_reo->Text.ToDouble();
 fc=fc_concrete->Text.ToDouble();
 b=B_width->Text.ToDouble();
 
 
 
 d=dd-c-db*0.5;
 
 
 asr=(1-sqrt(1-3000000*m/(b*d*d*fc)))/(1.2*(f/(b*d*fc)));
 as_min=b*d*0.22*pow((dd/d),2)*0.6*(sqrt(fc))/f;
 
 
 d_depth->Text=String(d);
 Astr->Text=String(asr);
 
 Astm->Text=String(as_min);
 
 
return;

                                  
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Asked On
2009-10-29 at 21:21:25ID24857068
Tags

Embarcadero C++ 2010

Topic

C++ Builder

Participating Experts
2
Points
125
Comments
2

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Answers

 

by: KdoPosted on 2009-10-30 at 05:12:30ID: 25702114

Hi Pete,

There are a LOT of ways to do this with C++.  All of the traditional C functions are available to you, and the Borland/VCL extensions.  Pick your poison, so to speak.  :)

  sprintf (StringBuffer, "%10.2lf", double_value);   //  Put formatted string in StringBuffer using C function.

  MyString = Format ("%10.2lf", ARRAYOFCONST((double_value)));  // requires Sysutils.h

  The FloatToStrF, Format, and FormatFloat methods of the AnsiString (String) class may also work for you.


Good Luck,
Kent


 

by: gtokasPosted on 2009-10-30 at 16:03:54ID: 25707332

You can also use FloatToStr() command and limit the number of characters after the mantissa.

George Tokas.

20120131-EE-VQP-002

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