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scalainheritancemultiple-inheritance

I am trying to initialise a Base Class property of a Sub Class but I am getting an error in Scala

I am trying to make this Sub Class Circle inherit the traits of parent class Shapes. I want the Circle Class to accept a colour string but I keep getting an error.

abstract class Shape  {
 def getArea():Double 
 var colour = "Red"

 def getColour():String = colour
 def setColour(newColour:String) = {
   colour = newColour 

 }
}

case class Circle (var radius:Int, override var colour:String) extends Shape {
  override def getArea():Double = 3.14 * radius * radius 
}

The error I get is:

"ScalaFiddle.scala:13: error: overriding field colour in class Shape of type lang.this.String;"

Solution

  • You can't override a var but you can assign to it.

    case class Circle (var radius:Int, clr:String) extends Shape {
  colour = clr
  ...

    BTW, mutable variables are dangerous. Just pretend that var doesn't exist. You'll write better code without it.