public Set Union(Set c2)
{
Set c = new Set();
for (int i = 0; i < this.NumberofElements(); i++)
c.Add(this.Element(i + 1));
for (int i = 0; i < c2.NumberofElements(); i++)
if (!c.Contains(c2.Element(i + 1)))
c.Add(c2.Element(i + 1));
return (c);
}
public Set Intersection(Set c2)
{
Set c = new Set();
for (int i = 0; i < this.NumberofElements(); i++)
if (c2.Contains(this.Element(i + 1)))
c.Add(this.Element(i + 1));
return (c);
}
public Set Substract(Set c2)
{
Set c3 = new Set(); Set c = new Set();
c3 = this.Intersection(c2);
for (int i = 0; i < this.NumberofElements(); i++)
if (c3.Contains(this.Element(i + 1)) == false)
c.Add(this.Element(i + 1));
return (c);
}