Adding a Dynamic List in Java

DynamicList.java

@@ -0,0 +1,166 @@
+import java.util.Scanner;
+
+public class DynamicList {
+
+    public static Scanner sc = new Scanner(System.in);
+    public static void main(String [] args) throws Exception{
+
+        List list = new List();
+
+        list.insertEnd(3);
+        list.insertBegin(0);
+        list.insert(1, 1);
+        list.insert(2, 2);
+        list.insertEnd(5);
+
+        list.print();
+
+        list.remove(4);
+
+        list.print();
+
+    }
+
+}
+
+    class Cell {
+
+        public int element;
+        public Cell next; 
+
+        public Cell(){
+            this(0);
+        }
+
+        public Cell(int element) {
+          this.element = element;
+          this.next = null;
+        }
+    }
+
+    class List {
+
+        private Cell first;
+        private Cell last;
+
+        public List() {
+            first = new Cell();
+            last = first;
+        }
+
+        public void insertBegin(int x) {
+            Cell tmp = new Cell(x);
+            tmp.next = first.next;
+            first.next = tmp;
+            if (first == last) {                 
+                last = tmp;
+            }
+          tmp = null;
+        }
+
+        public void insertEnd(int x) {
+            last.next = new Cell(x);
+            last = last.next;
+        }
+
+        public int removeBegin() throws Exception {
+
+            if (first == last) {
+                throw new Exception("Error! List is empty!");
+            }
+
+            Cell tmp = first;
+            first = first.next;
+            int resp = first.element;
+            tmp.next = null;
+            tmp = null;
+
+            return resp;
+        }
+
+
+        public int removeEnd() throws Exception {
+
+            if (first == last) {
+                throw new Exception("Error! List is empty!");
+            } 
+
+            Cell i;
+            for(i = first; i.next != last; i = i.next);
+
+            int resp = last.element; 
+            last = i; 
+            i = last.next = null;
+
+            return resp;
+        }
+
+       public void insert(int x, int pos) throws Exception {
+
+          int size = size();
+
+          if(pos < 0 || pos > size){
+                throw new Exception("Error! Position (" + pos + " / size = " + size + ") invalid!");
+          } else if (pos == 0){
+             insertBegin(x);
+          } else if (pos == size){
+             insertEnd(x);
+          } else {
+             Cell i = first;
+             for(int j = 0; j < pos; j++, i = i.next);
+
+             Cell tmp = new Cell(x);
+             tmp.next = i.next;
+             i.next = tmp;
+             tmp = i = null;
+          }
+       }
+
+        public int remove(int pos) throws Exception {
+
+          int resp;
+          int size = size();
+
+            if (first == last){
+                throw new Exception("Error! List is empty!");
+
+          } else if(pos < 0 || pos >= size){
+                throw new Exception("Error! Position (" + pos + " / size = " + size + ") invalid!");
+          } else if (pos == 0){
+             resp = removeBegin();
+          } else if (pos == size - 1){
+             resp = removeEnd();
+          } else {
+             Cell i = first;
+             for(int j = 0; j < pos; j++, i = i.next);
+
+             Cell tmp = i.next;
+             resp = tmp.element;
+             i.next = tmp.next;
+             tmp.next = null;
+             i = tmp = null;
+          }
+
+            return resp;
+        }
+
+        public void print() {
+
+            int position = 0;
+
+            for (Cell i = first.next; i != null; i = i.next) {
+
+                System.out.print("[" +position+ "]" + i.element + " ");
+                position++;
+            }
+
+            System.out.println();
+        }
+
+       public int size() {
+          int size = 0; 
+          for(Cell i = first; i != last; i = i.next, size++);
+          return size;
+       }
+
+    }