Which should inherit what?

Question

This is one of OOP’s boring academic questions, but it’s not homework. I got a question from a novice programmer about one of these silly examples of OOP tutorials.

Imagine that you are designing a square class and a Cube class that should inherit which?

I see a relationship, but what it is, I really don’t see!

Could you give me a logical argument in the mind of OOP.

Answer 1

None! Since a square is not a cube, and a cube is not a square, none of them should inherit from the other. A square can inherit from a polygon, and a cube can inherit from a polyhedron, but both of them are mutually exclusive.

Answer 2

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Answer 3

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Answer 4

Answer 5

struct Square // Rectangle actually
{
  Square( int dx, int dy ) : dx(dx), dy(dy) {};

  int dx;
  int dy;

  int floor_area() { return dx*dy; };
};

struct Cube : Square  // Cuboid actually
{
  Cube( int dx, int dy, int dz ) : Square(dx, dy), dz(dz) {};

  int dz;

  int cube_area() { return floor_area()*2+dx*dz*2+dy*dz*2; };
};

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Answer 6

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Answer 7

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Answer 8

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