Create Linkedlist-insertion (hacktoberfest17#931)

Author: Nickx58

linked_list/java/Linkedlist-insertion

@@ -0,0 +1,66 @@
+package linkedlist;
+
+class LinkedList {
+    Node head;
+    
+    static class Node {
+        int data;
+        Node next;
+        
+        Node(int data) {
+            this.data = data;
+            next = null;
+        }
+    }
+    
+    public void printList() {
+        Node n = head;
+        while(n!=null) {
+            System.out.print(n.data+" ");
+            n = n.next;
+        }
+    }
+    
+    public void push(int data) {
+        Node new_node = new Node(data);
+        new_node.next = head;
+        head = new_node;
+    }
+    
+    public void insertAfter(Node prev_node, int data) {
+        if(prev_node == null) {
+            System.out.print("Prev Node cannot be null");
+            return;
+        }
+        
+        Node new_node = new Node(data);
+        new_node.next = prev_node.next;
+        prev_node.next = new_node;
+    }
+    
+    public void append(int data) {
+        Node new_node = new Node(data);
+        if(head == null) {
+            head = new Node(data);
+            return;
+        }
+        new_node.next = null;
+        Node last = head;
+        while(last.next != null){
+            last = last.next;
+        }
+        
+        last.next = new_node;
+        return;
+       
+       
+    }
+    public static void main(String args[]) {
+        LinkedList ll = new LinkedList();
+        ll.push(8);
+        ll.append(7);
+        ll.append(5);
+        ll.printList();
+        
+    }
+}