implement_interface.go

// Implement Geometry interface
func (r Rectangle) area() float32 {
	return r.length * r.breadth
}

// Implement Geometry interface
func (r Rectangle) parameter() float32 {
	return 2 * (r.length + r.breadth)
}

// Implement Geometry interface
func (r Rectangle) numOfSides() int {
	return 4
}

// Implement color interface
func (r Rectangle) getColor() string {
	return r.color
}