Number always outputs as decimal in edit box, regardless if it is an int or a double-CodePudding

I'm pretty new to coding and for the last couple of days I've been exploring WINAPI and trying to learn something new, so I decided to make a calculator (honestly, was harder than I anticipated).

Now I've got everything working, but the only problem left is that when I try to use the calculator, I always get a result that looks like this: 22 22 = 44.0000000. Is there a way I could maybe format the Edit box to show decimal numbers only when needed or maybe there is something I have done wrong in the function?

I included one of the computing functions (used for multiplication) below:

void multiply() {
    WCHAR A[20], B[20];

    GetWindowText(hOutputBot, A, 20);
    GetWindowText(hOutputTop, B, 20);

    double Aa = std::stof(A);
    double Bb = std::stof(B);
    
    double Res = Bb * Aa;

    std::wstring s = std::to_wstring(Res);

    LPCWSTR str = s.c_str();

    SetWindowTextW(hOutputBot, str);
}

CodePudding user response：

Custom formatting is not really available when you use the std::to_string() function. Instead, what you can do is to use the standard formatted output operator to write your data to a string stream, then read your std::string from that:

//  std::wstring s = std::to_wstring(Res);
    std::wstringstream ss;  ss << Res; // Write value to string stream
    std::wstring s;         ss >> s;  // ... then read it into string.
    //...
    LPCWSTR str = s.c_str();

(Note that you will need to #include <sstream>.)

The default format of the output of a double type is similar to using the %lg format specifier in the C-style printf() function; however, you can add further customizations – should you so desire – using the various functions in the <iomanip> standard header.