Update file LinkedListExample.kt

src/main/kotlin/lecture8/LinkedListExample.kt

 package lecture8
 
+class LinkedList(){
+    var head: Node<T>? = null
+    
+    class Node<T>(val data: T, var next: Node<T> = null){ //initialize it as null by default
+        fun add(node: Node<T>){
+            if (next == null) {
+                next = node
+            } else {
+                next?.add(null)
+            }
+        }
+
+        fun next() = next
+
+    }
+    fun add(t: T){
+        if(head == null){
+            head = Node (t)
+        } else {
+            head?.add(Node(t))
+        }
+    }
+
+    override fun toString(): String{
+        val sb = StringBuilder()
+        //iterate thorugh elements
+        sb.append("[")
+        sb.append(head.toString())
+        var current = head
+        while (current!=){
+            sb.append(", ")
+            sb.append(current.toString())
+            current = current.next
+
+        }
+        sb.append("]")
+        return sb.toString()
+
+    }
+
+    fun forEach(f: (T) -> Unit) {
+        f(head?.data)
+        var current = head?.next
+        while (current!=null){
+            //line to apply f to element
+            f(current?.data)
+            current = current.next
+        }
+    }
+
+}
+
+// if we want default arguments in a function, you want to put it at the end of all arguments, otherwise you have to use keywords(???)
+
+fun main(){
+    val l = linkedList<Int>()
+    l.add(6)
+    l.add(12)
+    l.add(40009)
+    l.add(2)
+    
+    println(l)
+    l.forEach {x -> println(x)}
+}
+