CSE143 Sample Program              handout #2
Client Program ArrayIntListSample.java
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public class ArrayIntListSample {
    public static void main(String[] args) {
        ArrayIntList list = new ArrayIntList(25);
        list.add(3);
        list.add(7);
        list.add(11);
        System.out.println("initial list = " + list);
        list.add(0, 2);
        list.add(2, 5);
        System.out.println("after some adds = " + list);
        System.out.print("index of:");
        for (int i = 1; i < 10; i += 2)
            System.out.print("   " + i + " -> " + list.indexOf(i));
        System.out.println();
        System.out.print("get:");
        for (int i = 0; i < list.size(); i++)
            System.out.print("   " + i + " -> " + list.get(i));
        System.out.println();
        System.out.println("list = " + list);
        while (list.size() > 0) {
            int i = (int) (Math.random() * list.size());
            list.remove(i);
            System.out.println("after removing at " + i + " list = " + list);
        }
    }
}
Output of ArrayIntListSample.java
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initial list = [3, 7, 11]
after some adds = [2, 3, 5, 7, 11]
index of:   1 -> -1   3 -> 1   5 -> 2   7 -> 3   9 -> -1
get:   0 -> 2   1 -> 3   2 -> 5   3 -> 7   4 -> 11
list = [2, 3, 5, 7, 11]
after removing at 4 list = [2, 3, 5, 7]
after removing at 0 list = [3, 5, 7]
after removing at 0 list = [5, 7]
after removing at 0 list = [7]
after removing at 0 list = []
Program ArrayIntList.java
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// Class ArrayIntList can be used to store a list of integers.
public class ArrayIntList {
    private int[] elementData; // list of integers
    private int size;          // current number of elements in the list
    public static final int DEFAULT_CAPACITY = 100;
    // post: constructs an empty list of default capacity
    public ArrayIntList() {
        this(DEFAULT_CAPACITY);
    }
    // pre : capacity >= 0 (throws IllegalArgumentException if not)
    // post: constructs an empty list with the given capacity
    public ArrayIntList(int capacity) {
        if (capacity < 0) {
            throw new IllegalArgumentException("capacity: " + capacity);
        }
        elementData = new int[capacity];
        size = 0;
    }
    // post: returns the current number of elements in the list
    public int size() {
        return size;
    }
    // pre : 0 <= index < size() (throws IndexOutOfBoundsException if not)
    // post: returns the integer at the given index in the list
    public int get(int index) {
        checkIndex(index);
        return elementData[index];
    }
    // post: creates a comma-separated, bracketed version of the list
    public String toString() {
        if (size == 0) {
            return "[]";
        } else {
            String result = "[" + elementData[0];
            for (int i = 1; i < size; i++) {
                result += ", " + elementData[i];
            }
            result += "]";
            return result;
        }
    }
    // post : returns the position of the first occurrence of the given
    //        value (-1 if not found)
    public int indexOf(int value) {
        for (int i = 0; i < size; i++) {
            if (elementData[i] == value) {
                return i;
            }
        }
        return -1;
    }
    // post: returns true if list is empty, false otherwise
    public boolean isEmpty() {
        return size == 0;
    }
    // post: returns true if the given value is contained in the list,
    //       false otherwise
    public boolean contains(int value) {
        return indexOf(value) >= 0;
    }
    // pre : size() < capacity (throws IllegalStateException if not)
    // post: appends the given value to the end of the list
    public void add(int value) {
        add(size, value);
    }
    // pre : size() < capacity (throws IllegalStateException if not) &&
    //       0 <= index <= size() (throws IndexOutOfBoundsException if not)
    // post: inserts the given value at the given index, shifting subsequent
    //       values right
    public void add(int index, int value) {
        if (index < 0 || index > size) {
            throw new IndexOutOfBoundsException("index: " + index);
        }
        if (size + 1 > elementData.length) {
            throw new IllegalStateException("would exceed list capacity");
        }
        for (int i = size; i > index; i--) {
            elementData[i] = elementData[i - 1];
        }
        elementData[index] = value;
        size++;
    }
    // pre : 0 <= index < size() (throws IndexOutOfBoundsException if not)
    // post: removes value at the given index, shifting subsequent values left
    public void remove(int index) {
        checkIndex(index);
        for (int i = index; i < size - 1; i++) {
            elementData[i] = elementData[i + 1];
        }
        size--;
    }
    // post: throws an IndexOutOfBoundsException if the given index is
    //       not a legal index of the current list
    private void checkIndex(int index) {
        if (index < 0 || index >= size) {
            throw new IndexOutOfBoundsException("index: " + index);
        }
    }
}