Floating point overflow

s+=r;

#include <vcl.h>
 
#pragma hdrstop
 
#include <math.h>
#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------
double fac( double x ) {
 return x == 0 ? 1 : x * fac( x - 1 );
}
void __fastcall TForm1::FormCreate(TObject *Sender)
{
Edit1->Text="0,1"; Edit2->Text="1,0"; Edit3->Text="10"; Edit4->Text="0,2";
Memo1->Lines->Add("Выполнил работу И.Н");
}
 
//---------------------------------------------------------------------------
 
void __fastcall TForm1::Button1Click(TObject *Sender)
{
 double a, b, x, h, r, s, zn, k;
 int n( 50 );
for(x = a; x<=b; x+=h)
 r = s = 1;
for(k = 1; k<=n; k++ ){
r = zn*r*x/k;
s+=r;
}
 a = StrToFloat(Edit1->Text);
 b = StrToFloat(Edit2->Text);
 n = StrToInt(Edit3->Text);
 h = StrToFloat(Edit4->Text);
Memo1->Lines->Add("при x= " + FloatToStrF(x,ffFixed,8,2)
+ " сумма= " + FloatToStrF(s,ffFixed,8,5));
}

for ( x = a; x <= b; x += h, s = 0 )

for ( double k = 0; k < n; s += pow( - 1., k ) * pow( x, 2. * k ) / fac( 2 * k ), ++k );

#include <vcl.h>
#pragma hdrstop
#include <math.h>
#include <iostream.h>
//---------------------------------------------------------------------------
 
#pragma argsused
 
using namespace std;
 
 double fac( double x ) {
 return x == 0 ? 1 : x * fac( x - 1 );
}
int main()
{
//////////////////////////////////////
double a( 0.1 ), b( 1 ), h( 0.1 ), x, y, s( 0 );
int n( 50 );
for ( x = a; x <= b; x += h, s = 0 ) {
cout << endl << "y(" << x << ") = " << ( y = cos( x ) ) << "\t";
for ( double k = 0; k < n; s += pow( - 1., k ) * pow( x, 2. * k ) / fac( 2 * k ), ++k );
cout << "s(" << x << ") = " << s << "\t";
cout << "| y(" << x << ") - s(" << x << ") | = " << fabs( y - s );
}
{
      return 0;
}
}