static void Main4()
{
DaThuc d1 = new DaThuc();
DaThuc d2 = new DaThuc();
Console.WriteLine("Da thuc thu nhat"); d1.Hien();
Console.WriteLine("Da thuc thu hai"); d2.Hien();
DaThuc d3 = d1.Tong(d2);
DaThuc d4 = d1.Hieu(d2);
Console.WriteLine("Da thuc tong"); d3.Hien();
Console.WriteLine("Da thuc hieu"); d4.Hien();
Console.ReadLine();
}
public DaThuc Hieu(DaThuc t2)
{
if (this.n == t2.n)
{
DaThuc d = new DaThuc(this.n);
for (int i = 0; i < n; i++)
{
d.a[i] = this.a[i] - t2.a[i];
}
return(d);
}
else
{
return(null);
}
}
