void __fastcall TForm1::RadioButton1Click(TObject *Sender)
{
    RadioButton1->Checked = true;
    Memo1->ShowHint = true;
    if (RadioButton1->Checked == true) {
        RadioButton1->ShowHint = true;
        RadioButton1->Hint = "라디오 버튼1 클릭됨";
        Memo1->Text = "Check1: Checked";
    }
}
//---------------------------------------------------------------------------
void __fastcall TForm1::RadioButton2Click(TObject *Sender)
{
    RadioButton2->Checked = true;
    RadioButton2->ShowHint = true;
    if (RadioButton2->Checked == true)
        Memo1->Text = "Unchecked";
    else {
        Memo1->Text = "Checked";
        RadioButton2->Hint = "라디오 버튼2 클릭됨";
        RadioButton2->ShowHint = true;
    }
}
//---------------------------------------------------------------------------
void __fastcall TForm1::RadioButton3Click(TObject *Sender)
{
    RadioButton3->Checked = true;
    RadioButton3->ShowHint = true;
    if (RadioButton3->Checked == true)
        Memo1->Text = "UnChecked";
    else {
        RadioButton3->Hint = "라디오 버튼3 클릭됨";
        Memo1->Text = "Checked";
    }
}
//---------------------------------------------------------------------------

위 소스를 기록하고 F9를 누르면
[ilink32 Error] Error: Unresolved external '__fastcall TForm1::GroupBox1Click(System::TObject *)' referenced from E:\PROGRAMMING DEVELOPMENT\PROGRAME SOURCES\C++BUILDER\실습_6-2 TRADIOBUTTON 컨트롤\WIN32\DEBUG
\UNIT1.OBJ 에러가 납니다.

해결하기에 좋은 점 있다면 알려주세요.