hashTableLab

258/iteratorLab/DLList.java

@@ -0,0 +1,154 @@
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+// Doubly Linked List
+public class DLList<T> implements Iterable<T> {
+
+    // Main method to test this class
+    public static void main(String[] args) {
+        // Add random numbers to a new list:
+        DLList<Integer> aList = new DLList<Integer>();
+        for (int i = 0; i < 20; i++) aList.add((int) (Math.random() * 100));
+
+        // Print list using for-each loop:
+        for (Integer i : aList) System.out.print(i + " ");
+        System.out.println();
+
+        // Print list using iterator methods:
+        DLList<Integer>.DLListIterator iter = aList.iterator(20);
+        while (iter.hasPrevious()) System.out.print(iter.previous() + " ");
+        System.out.println();
+
+        while (iter.hasNext()) System.out.print(iter.next() + " ");
+        System.out.println();
+
+        while (iter.hasPrevious()) System.out.print(iter.previous() + " ");
+        System.out.println();
+    }
+
+    private class Node {
+
+        T element;
+        Node next;
+        Node prev;
+
+        public Node(T element) {
+            this.element = element;
+        }
+    }
+
+    // Linked List Iterator class
+    private class DLListIterator implements Iterator<T> {
+
+        private Node walker;
+
+        private DLListIterator() {
+            walker = head;
+        }
+
+        private DLListIterator(Integer index) {
+            walker = head;
+
+            for (int i = 0; i < index; i++) {
+                next();
+            }
+        }
+
+        @Override
+        public boolean hasNext() {
+            return walker != null;
+        }
+
+        public boolean hasPrevious() {
+            return walker == null || walker.prev != null;
+        }
+
+        @Override
+        public T next() {
+            if (hasNext()) {
+                T element = walker.element;
+                walker = walker.next;
+                return element;
+            } else throw new NoSuchElementException();
+        }
+
+        public T previous() {
+            if (hasPrevious()) {
+                if (walker == null) {
+                    walker = tail;
+                } else {
+                    walker = walker.prev;
+                }
+
+                T element = walker.element;
+
+                return element;
+            } else throw new NoSuchElementException();
+        }
+    }
+
+    private Node head;
+    private Node tail;
+    private int size;
+
+    // Add to end of list
+    public void add(T element) {
+        add(size, element);
+    }
+
+    // Add to list at given index
+    public void add(int index, T element) {
+        if (index < 0 || index > size) throw new IndexOutOfBoundsException(
+            "" + index
+        );
+        Node n = new Node(element);
+        if (head == null) {
+            // list empty
+            head = tail = n;
+        } else if (index == 0) {
+            // add to head
+            n.next = head;
+            head.prev = n;
+            head = n;
+        } else if (index == size) {
+            // add to tail
+            n.prev = tail;
+            tail.next = n;
+            tail = n;
+        } else {
+            // general case
+            Node walker = head;
+            for (int i = 0; i < index - 1; i++) walker = walker.next;
+            n.next = walker.next;
+            n.prev = walker;
+            walker.next = n;
+            n.next.prev = n;
+        }
+        size++;
+    }
+
+    public int size() {
+        return size;
+    }
+
+    @Override
+    public String toString() {
+        if (size == 0) return "[]";
+        String s = "[";
+        Node walker = head;
+        while (walker != tail) {
+            s += walker.element + ", ";
+            walker = walker.next;
+        }
+        return s + walker.element + "]";
+    }
+
+    @Override
+    public Iterator<T> iterator() {
+        return new DLListIterator();
+    }
+
+    public DLListIterator iterator(Integer i) {
+        return new DLListIterator(i);
+    }
+}

344/arro/arro.plcc

@@ -0,0 +1,49 @@
+skip WHITESPACE '\s+'
+
+token NUM           '[0-9]+'
+token VAR           '[A-Za-z_][A-Za-z0-9_]*'
+
+token OP            '\+|-'
+token MOP           '\*|/'
+
+token IN            '==>'
+token OUT           '<=='
+token ASSIGN         '->'
+
+token LOOP          '\?\?'
+token IF             '\?'
+token ELSE           '\|'
+
+token LPAREN        '\('
+token RPAREN        '\)'
+token LBRACE        '\{'
+token RBRACE        '\}'
+token SEMI          ';'
+
+token OP '\+|-'
+token MOP '\*|/'
+
+%
+
+<program> ::= <stmtlist>
+
+<stmtlist> **= <stmt>
+
+<stmt>InputStmt ::= <IN> <VAR> <SEMI>
+<stmt>OutputStmt ::= <OUT> <exp> <SEMI>
+<stmt>AssignStmt ::= <VAR> <ASSIGN> <exp> <SEMI>
+
+<stmt>ControlStmt ::= <LPAREN> <exp> <RPAREN> <ctrltail>
+
+<ctrltail>IfStmt ::= <IF> <block> <ELSE> <block>
+<ctrltail>LoopStmt ::= <LOOP> <block>
+
+<block> ::= <LBRACE> <stmtlist> <RBRACE>
+
+<exp> ::= <mult> <exprest>
+<exprest> **= <OP> <mult>
+<mult> ::= <value> <multrest>
+<multrest> **= <MOP> <value>
+<value> ::= <NUM> | <VAR>
+
+%