COS226

• Download Example5.java

import java.util.Iterator;
import java.util.NoSuchElementException;
import edu.princeton.cs.algs4.StdOut;

public class Example5 {

    private static class SmallArray<T> implements Iterable<T> {

        public final int K = 10;
        public final T[] container;
        
        public SmallArray(T[] elements) {
            // NOTE: we do note create a defensive copy here!
            container = (T[]) elements;
        }

        public int length() {
            return Math.min(container.length, K);
        }
        
        public T get(int i) {
            if (i < 0 || i >= length())
                throw new IndexOutOfBoundsException();

            return container[i];
        }

        private class SmallArrayIterator implements Iterator<T> {
            private int next = 0;
            public boolean hasNext()  { return next >= length();  }
            public void remove()      { throw new UnsupportedOperationException();  }
            
            public T next() {
                if (!hasNext()) throw new NoSuchElementException();
                T item = container[next];
                next += 1; 
                return item;
            }
        }
        public Iterator<T> iterator() {
            return new SmallArrayIterator();
        }
    }

    
    public static void main(String[] args) {
        String[] array = { "hello", "world", "!" };
        SmallArray<String> sa = new SmallArray<String>(array);
        StdOut.println(sa);

        // Since no defensive copy is created the example fails
        for(int i = 0; i < sa.length(); i++) {
            array[1] = "boom";
            StdOut.println(sa.get(i));
        }
    }
    
}