Overriding error.. pls advise me

[Tampopo]

I kept getting this error:

Line3D.h:18:13: error: invalid covariant return type for ‘virtual Point3D Line3D::getPt1()’
Line2D.cpp:41:9: error: overriding ‘virtual Point2D Line2D::getPt1()’
Line3D.h:20:13: error: invalid covariant return type for ‘virtual Point3D Line3D::getPt2()’
Line2D.cpp:52:9: error: overriding ‘virtual Point2D Line2D::getPt2()’

The following is at these portions:

Line3D.h:18:
Point3D getPt1();

Line2D.cpp:41:9

Point2D Line2D::getPt1() 
{
   return pt1;
}

Line3D.h:20
Point3D getPt2();

Line2D.cpp:52

Point2D Line2D::getPt2() 
{
   return pt2;
}

What have i done wrong here?

The requirement states:
+ getPt1 () : Point2D
+ getPt2 () : Point2D

+ getPt1 () : Point3D
+ getPt2 () : Point3D

The bottom function inherit from the function on top..

[Tampopo]

Any help on this error?

[coder777]

You cannot have different return types with the same function name. You may name it like so:

Point3D get3DPt1();
Point2D get2DPt1();

[Tampopo]

Thanks