/** The ArrayIntList class stores an ordered list of integers.
 *  @author Adam Blank
 */

import java.util.*;

public class ArrayIntList implements IntList, Iterable<Integer> {
    private int size;
    private int[] data;
    
    /*
     
     DEFAULT_CAPACITY = 5
     ArrayIntList list = new ArrayIntList();
     list.add(5);
     list.add(2);
     list.add(17);
     CLIENT:      [5, 2, 17]
     IMPLEMENTOR: [5, 2, 17, 0, 0]
     * 
     */
    
    public int numberOfEvens() {
        int result = 0;
        /*
        for (int i = 0; i < this.size; i++) {
            if (this.data[i] % 2 == 0) {
                result++;
            }
        }
        
        
        Iterator<Integer> it = this.iterator();
        while (it.hasNext()) {
            if (it.next() % 2 == 0) {
                result++;
            }
        }
        */
        
        for (int i : this) {
            if (i % 2 == 0) {
                result++;
            }

        }
        return result;
    }

    
    
    
    
    
    
    
    
    
    
    

    public static final int DEFAULT_CAPACITY = 100000;

    private class ArrayIntListIterator implements Iterator<Integer> {
        private int last;

        public ArrayIntListIterator() {
            this.last = -1;
        }

        public boolean hasNext() {
            return (this.last + 1) < ArrayIntList.this.size; 
        }

        public Integer next() {
            this.last++;
            return ArrayIntList.this.data[this.last];
        }

        public void remove() {
            throw new UnsupportedOperationException();
        }
    }

    /** Initializes a new empty list with initial capacity of DEFAULT_CAPACITY integers. */
    public ArrayIntList() {
        this.data = new int[DEFAULT_CAPACITY];
        this.size = 0;
    }

    /** Returns a new iterator for the list */
    public Iterator<Integer> iterator() {
        return new ArrayIntListIterator();
    }
    
    public boolean search(int value) {
        for (int i = 0; i < this.size(); i++) {
            if (this.get(i) == value) {
                return true;
            }
        }
        return false;
    }


    /** 
     * Appends value to the end of the list. <br><br>
     * post: value is appended to the ArrayList 
     */
    public void add(int value) {
        this.grow(this.size);
        this.data[this.size] = value;
        this.size++;
    }

    /** 
     * Returns the value at index. <br><br>
     * pre: 0 <= index <= size otherwise throws IndexOutOfBoundsException 
     */ 
    public int get(int index) {
        checkIndex(index);
        return this.data[index];
    }

    /** 
     * Sets the data at index to value. <br><br>
     * pre: 0 <= index <= size otherwise throws IndexOutOfBoundsException
     */
    public void set(int index, int value) {
        checkIndex(index);
        if (index == this.size) {
            this.size++;
        }
        this.data[index] = value;
    }

    /** 
     * Removes the value at the given index, shifting later values over. <br><br>
     * pre: 0 <= index < size otherwise throws IndexOutOfBoundsException
     */
    public void remove(int index) {
        checkIndex(index);
        for (int i = index; i < this.size - 1; i++) {
            this.set(i, this.get(i+1));
        }
        this.size--;
    }

    /** Returns the number of elements in the list. */
    public int size() {
        return this.size;
    }

    /** 
     * Returns a String representation of the list consisting of the elements
     * in order, separated by commas and enclosed in square brackets. 
     */
    public String toString() {
        String result = "";
        if (this.size > 0) {
            result = "" + this.data[0];
            for (int i = 1; i < this.size; i++) {
                result += ", " + this.data[i];
            }
        }
        return "[" + result + "]";
    }

    /** 
     * Grows the ArrayIntList to have room for *at least* requiredCapacity elements. <br><br>
     * pre: 0 <= requiredCapacity otherwise throws IllegalArgumentException
     */ 
    private void grow(int requiredCapacity) {
        if (requiredCapacity < 0) {
            throw new IllegalArgumentException();
        }

        if (requiredCapacity > this.data.length) {
            this.data = Arrays.copyOf(this.data, this.data.length * 2);
        }
    }

    /**
     * Checks if index is a valid index into this ArrayIntList. <br><br>
     * post: throws IndexOutOfBoundsException if index < 0 or index >= max 
     */ 
    private void checkIndex(int index) {
        if (0 > index || index >= this.size) {
            throw new IndexOutOfBoundsException();
        }
    }
       
}