Erreur dans ce petit programme c++ builder

bonsoir;

//---------------------------------------------------------------------------

#include <vcl.h>
#include <math.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
int a,b,c ;
float delta,r1,r2;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------



void __fastcall TForm1::Button1Click(TObject *Sender)
{
a=StrToInt(Edit1->Text);
b=StrToInt(Edit2->Text);
c=StrToInt(Edit3->Text);

delta=(b*b)-(4*(a*c));
Edit5->Text=FloatToStr(delta);
if(delta>0)
{
r1=(-b+sqrt(fabs(delta)))/(2*a);
r2=(-b-sqrt(fabs(delta)))/(2*a);
}
if(delta<0)
{
r1=(-b+(sqrt(fabs(delta))))/(2*a);
r2=(-b-(sqrt(fabs(delta))))/(2*a);
}

Edit6->Text=FloatToStr(r1);
Edit7->Text=FloatToStr(r2);
}
//---------------------------------------------------------------------------


void __fastcall TForm1::Button3Click(TObject *Sender)
{
Close(); a=0,b=0,c=0,delta=0;
}
//---------------------------------------------------------------------------


void __fastcall TForm1::Button2Click(TObject *Sender)
{
a=0,b=0,c=0,delta=0;
Edit1->Clear();
Edit2->Clear();
Edit3->Clear();
Edit4->Clear();
Edit5->Clear();
Edit6->Clear();
Edit7->Clear();
}
//---------------------------------------------------------------------------