Проверить, все ли элементы столбца матрицы нулевые

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
 
#include "Unit1mass.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
const Nmax=10;
typedef double mas2[Nmax][Nmax];
typedef double mas1[Nmax];
int n;
//---------------------------------------------------------------------------
void __fastcall TForm1::FormCreate(TObject *Sender)
{
Edit1->Text=FloatToStr(n);
StringGrid1->ColCount=n+1;
StringGrid1->RowCount=n+1;
StringGrid2->RowCount=n+1;
StringGrid1->Cells[0][0]="Ìàññèâ À";
StringGrid2->Cells[0][0]="Ìàññèâ Á";
for(int i=1; i<=n; i++)
{
StringGrid1->Cells[0][i]="i="+IntToStr(i);
StringGrid1->Cells[i][0]="k="+IntToStr(i);
}
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::Button1Click(TObject *Sender)
{
n=StrToInt(Edit1->Text);
StringGrid1->ColCount=n+1;
StringGrid1->RowCount=n+1;
StringGrid2->RowCount=n+1;
StringGrid1->Cells[0][0]="Ìàññèâ À";
StringGrid2->Cells[0][0]="Ìàññèâ Á";
for(int i=1; i<=n; i++)
{
StringGrid1->Cells[0][i]="i="+IntToStr(i);
StringGrid1->Cells[i][0]="k="+IntToStr(i);
}
}
//---------------------------------------------------------------------------
 
void __fastcall TForm1::Button2Click(TObject *Sender)
{
mas2 a;
mas1 b;
int i,k;
for(i=0;i<n;i++)
for(k=0;k<n;k++)
a[i][k]=StrToFloat(StringGrid1->Cells[i+1][k+1]);
int s=0,p=1;
for(k=0;k<n;k++)
for(i=0;i<n;i++)
{
s=s+a[i][k];
p*=a[i][k];
}
if(p*=0) b[i]=0;
else b[i]=1;
for(i=0;i<n;i++)
StringGrid2->Cells[0][k+1]=FloatToStr(b[i]);
}
//---------------------------------------------------------------------------