CODEWITHSUNDEEP
scalaobjectabstract-class
user3619698
user3619698

Reputation: 135

Can an object extend abstract class in scala?

I am newbie to scala . I am trying to create an Object that extends abstract class like show below

object Conversions extends UnitConversions
{
 override def inchesToCentimeters(inches:Int) = inches * 2.5
 override def gallonsToLiters(gallons:Int) = gallons * 3.78
 override def milesToKilometers(miles:Int) = miles * 1.6
}

abstract class UnitConversions
{
 def inchesToCentimeters(inches:Int)
 def gallonsToLiters(gallons:Int)
 def milesToKilometers(miles:Int)
}

While i try to access the object's member functions i get () this expression as output .

Conversions.milesToKilometers(20) //I get output ()

More over is the below statement valid ???

var ucv:UnitConversions = new Conversions
println(ucv.milesToKilometers(3)) // I get output () here as well

Thanks in Advance !

Upvotes: 5

Views: 4673

Answers (2)

Jean Logeart
Jean Logeart

Reputation: 53819

You need to provide a return type for the functions, otherwise they return Unit:

abstract class UnitConversions {
  def inchesToCentimeters(inches:Int): Double
  def gallonsToLiters(gallons:Int): Double
  def milesToKilometers(miles:Int): Double
}

Upvotes: 9

corvus_192
corvus_192

Reputation: 422

Regarding this question:

More over is the below statement valid ???

var ucv:UnitConversions = new Conversions println(ucv.milesToKilometers(3))

This doesn't compile. object basically means singleton and can be used for "static" methods. It doesn't make sense to create more than one instance of a singleton. Take a look at this question: Difference between object and class in scala

Upvotes: 0

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