C++ 中的 Visual Studio MFC：为什么“int”有效而不是“double”？

Question

I'm using Visual Studio 2013 to build a UI using the MFC application. I use "Edit Control" to take three numerical inputs and a button that will produce a dialogue box that states the values of these inputs. When the variable from the Edit Control boxes are ints, it works properly. When they are doubles, I get 0's for two values and a random value for the third. Here is my code for the button press:

void CMFCApplication4Dlg::OnBnClickedButton2()
{
UpdateData();
CString temp2;
temp2.Format(_T("The frequency is %d Hz, the pulse width is %d ms, the duration is %d ms"), frequency, pulsewidth, duration);
MessageBox(temp2, 0, MB_ICONINFORMATION);
}

How can I make this work for doubles? My finished application will have to do some calculations that require decimals, so ints are not an option. I run into the same problem when I use floats too.

This is my first question and I'm not a very good programmer so I apologize if this is trivial.

Answer 1

That %d will only work with integers. Try %.2f . Excluding that last period. That should give you a number with two decimal places, but I haven't googled anything so check my syntax.