Example of using a min heap with case class

MinHeap.scala

object MinHeap {
        
  case class Dog(age:Int, name:String) extends Ordered[Dog]{
   def compare(that: Dog) = - this.age.compareTo(that.age)
  }
      
  val minHeap = scala.collection.mutable.PriorityQueue.empty[Dog]
                                                  //> minHeap  : scala.collection.mutable.PriorityQueue[MinHeap.Dog] = PriorityQue
                                                  //| ue()
  
  minHeap+=Dog(1,"Rusty")                         //> res0: MinHeap.minHeap.type = PriorityQueue(Dog(1,Rusty))
    
  minHeap+=Dog(12,"Max")                          //> res1: MinHeap.minHeap.type = PriorityQueue(Dog(1,Rusty), Dog(12,Max))
    
  minHeap+=Dog(5,"Spot")                          //> res2: MinHeap.minHeap.type = PriorityQueue(Dog(1,Rusty), Dog(12,Max), Dog(5,
                                                  //| Spot))

 // note, the toString of PQ doesn't obey order
                                                  
  minHeap.head                                    //> res3: MinHeap.Dog = Dog(1,Rusty)
  
  minHeap+=Dog(0,"Pup")                           //> res4: MinHeap.minHeap.type = PriorityQueue(Dog(0,Pup), Dog(1,Rusty), Dog(5,S
                                                  //| pot), Dog(12,Max))
  minHeap.head                                    //> res5: MinHeap.Dog = Dog(0,Pup)
  
  // don't use toList etc if you want the order to be obeyed, use dequeueAll. Note I clone first, as dequeuAll does mutate
   
  minHeap.clone.dequeueAll                        //> res6: scala.collection.immutable.IndexedSeq[MinHeap.Dog] = Vector(Dog(0,Pup)
                                                  //| , Dog(1,Rusty), Dog(5,Spot), Dog(12,Max))
  
  minHeap.dequeue()                               //> res7: MinHeap.Dog = Dog(0,Pup)
  
  minHeap.clone.dequeueAll                        //> res8: scala.collection.immutable.IndexedSeq[MinHeap.Dog] = Vector(Dog(1,Rust
                                                  //| y), Dog(5,Spot), Dog(12,Max))
}