По строчная запись в файл

    TFileStream *FS;
    TStringList *L = new TStringList();
    L->Text = Memo1->Text;
    try
    {
        FS = new TFileStream("test.txt", fmOpenWrite);
        int i = L->Text.Length();
        FS->Position = FS->Size;
        FS->Write(L->Text.c_str(), i * 2);
delete FS;
    }
    catch(...)
    {
        delete FS;
    }
    delete L;

#include <vcl.h>
#include <System.IOUtils.hpp>
#pragma hdrstop
 
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button1Click(TObject *Sender)
{
 TFile::AppendAllText("test.txt", Memo1->Text);
}
//---------------------------------------------------------------------------

TFile::AppendAllText("test.txt", Memo1->Text, TEncoding::UTF8);