Question

Java (Study Questions on Iterators and Introduction to Algorithm Complexity)

1) Look up the Iterator interface in the Java API. If a class implements this interface, what methods must it supply the code for? Include return types and parameter lists.

2) Look up the Iterable interface in the Java API. If a class implements this interface, what methods must it supply the code for?

Answer 1

An Iterator interface lets us iterator over a collection in java. The methods it must implement are

1. public boolean hasNext() : This method returns whether the iterator has any elements to itearate

2. public Object next() : This method returns the next element in the collection.

3. public void remove() : This method removes the current element in the collection.

class Lists implements Iterator{

@Override
public boolean hasNext() {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}

@Override
public Object next() {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}

@Override
public void remove() {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
  
}