Hands-On Object-Oriented Programming with Kotlin

Mutable sets

A mutable set is an extension of a set that supports adding and removing elements. Like a set, a mutable set does not provide its own function, but it does extend two interfaces: set and mutableCollection. Mutable sets also override all functions from their parent interfaces. This means that we can use all functions, including size, isEmpty, add, contains, and retainAll:

fun mutableSetFunction() {      val mutableSetItems : MutableSet<Int>    = mutableSetOf(1,1,2,3,3,4,5,5)     var mutableSetIterator =  mutableSetItems.iterator()      while (mutableSetIterator.hasNext()) {         print(mutableSetIterator.next())     }      println("")     println("Set size ${mutableSetItems.size}")      var item = 5     var result = mutableSetItems.contains(item) println("Mutable item ...