java iterators

Iterators

Q. What is an Iterable ?
A. Has a method that returns an Iterator.

public interface Iterable<Item>
{
    Iterator<Item> iterator();
}

Q. What is an Iterator ?

A. Has methods hasNext() and next().

public interface Iterator<Item>

{

    boolean hasNext();

    Item next();

    void remove();

}

Q. Why make data structures Iterable ?

A. Java supports elegant client code.

for (String s : stack){

    StdOut.println(s);

}

ref: http://algs4.cs.princeton.edu/home/