Save file dialog to save txt from array of numbers

Question

I would save my 2 arrays of ints and floats respectively into a "csv style" .txt file using a TSaveTextFileDialog. I am trying to do that in C++ Builder with a Windows VCL application. This is my attempt:

__fastcall TForm6::TForm6(TComponent* Owner)
    : TForm(Owner)
{
    saveTxtDlg = new TSaveTextFileDialog(this);

    TStrings* encodings = new TStringList();

    encodings->AddObject("UTF8", TEncoding::UTF8);

    saveTxtDlg->Encodings->Assign(encodings);

    saveTxtDlg->Filter = "Text files (*.txt)|*.TXT";
}

void __fastcall TForm6::Button2Click(TObject *Sender)
{
    if (saveTxtDlg->Execute(this->Handle))
    {
        String filename = saveTxtDlg->FileName + ".txt";

        int encIndex = saveTxtDlg->EncodingIndex;

        TEncoding* enc = dynamic_cast<TEncoding*>
            (saveTxtDlg->Encodings->Objects[encIndex]);

        int x[] = {1, 2, 3, 4, 5};
        float y[] = {10.1, 20.5, 30.8, 40.7, 50.2};

        for (int i = 0; i < 5; i++) {
            std::string s = std::to_string(x[i]) + "," + std::to_string(y[i]);
            s.SaveToFile(filename, enc);

        }

    }
}

But string has no member for "SaveToFile". How could I solve, please? Thank you in advance.

Answer 1

The dialog merely gives you filenames that the user has selected. You are responsible for actually opening those files and writing your data to them as needed.

For instance, have a look at things like TStringList::SaveToFile(), TFile::WriteAllText()/WriteAllLines(), TStreamWriter::Write()/WriteLine(), etc.

Try something like this:

void __fastcall TForm6::Button2Click(TObject *Sender)
{
    if (saveTxtDlg->Execute(this->Handle))
    {
        String filename = saveTxtDlg->FileName;

        int encIndex = saveTxtDlg->EncodingIndex;

        TEncoding* enc = static_cast<TEncoding*>(saveTxtDlg->Encodings->Objects[encIndex]);

        int x[] = {1, 2, 3, 4, 5};
        float y[] = {10.1, 20.5, 30.8, 40.7, 50.2};

        TStringList *txt = new TStringList;

        for (int i = 0; i < 5; ++i) {
            String s = String(x[i]) + _D(",") + String(y[i]);
            txt->Add(s);
        }

        txt->SaveToFile(filename, enc);
        delete txt;
    }
}

Alternatively:

#include <System.IOUtils.hpp>

void __fastcall TForm6::Button2Click(TObject *Sender)
{
    if (saveTxtDlg->Execute(this->Handle))
    {
        String filename = saveTxtDlg->FileName;

        int encIndex = saveTxtDlg->EncodingIndex;

        TEncoding* enc = static_cast<TEncoding*>(saveTxtDlg->Encodings->Objects[encIndex]);

        int x[] = {1, 2, 3, 4, 5};
        float y[] = {10.1, 20.5, 30.8, 40.7, 50.2};

        TStringDynArray txt;
        txt.Length = 5;

        for (int i = 0; i < 5; ++i) {
            String s = String(x[i]) + _D(",") + String(y[i]);
            txt[i] = s;
        }

        TFile::WriteAllLines(filename, txt, enc);
    }
}

Alternatively:

void __fastcall TForm6::Button2Click(TObject *Sender)
{
    if (saveTxtDlg->Execute(this->Handle))
    {
        String filename = saveTxtDlg->FileName;

        int encIndex = saveTxtDlg->EncodingIndex;

        TEncoding* enc = static_cast<TEncoding*>(saveTxtDlg->Encodings->Objects[encIndex]);

        int x[] = {1, 2, 3, 4, 5};
        float y[] = {10.1, 20.5, 30.8, 40.7, 50.2};

        TStreamWriter *txt = new TStreamWriter(filename, false, enc);

        for (int i = 0; i < 5; ++i) {
            String s = String(x[i]) + _D(",") + String(y[i]);
            txt->WriteLine(s);
        }

        txt->Flush();
        delete txt;
    }
}