Set Precision

char buffer[20];
double d = 1.23456 ;

sprintf(buffer, "%f", d);
MessageBox(NULL, buffer, "Without precision", MB_OK);

sprintf(buffer, "%.2f", d);
MessageBox(NULL, buffer, "With precision", MB_OK);

You can use stringstreams in connection with windows.

ostringstream ss;

ss << setprecision(n) << dblnum;

Now you can use ss.str() to get the string and copy it to wherever you want, messagebox or EditBox or wherever.

Alf

Yes, stringstream have my preference as well, dunno why I went into that C solution.

If you are using Code Warrior, use the WinSioux template and you can use cout << and get the result in a window which you can save.  I didn't discover this until recently.  It is absolutely brilliant when developing code on Win9x/ME where the maximum console buffer size is limited to 50 lines.

I am still confused about using ss.str();

Say I had:

// int = 100;
m_label1 = int * 5000;

How would I append the decimal places with the ss.str() method?

First off, if you have an integer it has no decimal places, if you have a floating point or double type you can format a value with precision.

Use the stringstream just like any other stream, a stringstream is a stream it just output the result in a memory buffer (a string using the ss.str() method to retrieve it) instead of outputting the result to a file or console.

So, if you know how to output a double type with precision to a console you can also make it to a string by using a stringstream instead of cout.

Exactly how you output that string to a window depends on what kind of platform you're on. In Visual C++ using MFC the way you would output the data would then be to first output to a ostringstream then retrieve the output as a string using ss.str() and just output that string to the window.

Something like this:

#include <sstream>
#include <iomanip>

void do_something()
{
   int k = 15;
   double x = 3.14;
   ostringstream ss;

   ss << "k = " << k << ", x = " << setprecision(3) << x;
   // Now, the ss.str is the string "k = 15, x = 3.14"
}

So your question boils down to: "How do I set a string to a label". I believe in Visual C++ in MFC you can set the label by:

m_label.SetWindowText(ss.str());

Note that this will convert the ss.str() to a CString string.

You can also use the Win32 function: ::SetWindowText( m_label -> m_hwnd,  ss.str()); This will NOT convert the string to a CString and will not involve a call to heap allocation. This latter call is therefore to be preferred if you want as little overhead as possible.

Alf

Can you substitute "ss" in:

ss << setprecision(n) << dblnum;

For a different value, so it can be used elsewhere?