08_stack kotlin version

kotlin/08_stack/StackBasedOnLinkedList.kt

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+/**
+ * 基于链表实现的栈。
+ *
+ * Author: Zackratos
+ */
+
+class StackBasedOnLinkedList {
+
+	private var top: Node? = null
+
+	fun push(value: Int) {
+		val newNode = Node(value, null)
+		// 不管 top 是不是 null，都可以这么写
+		newNode.next = top
+		top = newNode
+	}
+
+	fun pop(): Int {
+		if (top == null) return -1
+		val node = top
+		top = top!!.next
+		return node!!.data
+	}
+
+	fun printAll() {
+		var p = top
+		while(p != null) {
+			print("${p.data} ")
+			p = p.next
+		}
+		println()
+	}
+
+    class Node(var data: Int, var next: Node?)
+    
+}