public class MyGenericStack<E> {
    //char[] array=new char[10];
    E[] array = (E[])new Object[10];
    int size=0;
    boolean empty=true;

    public void push(E element) {
        if(size==array.length-1) {
            //System.out.println("The array is full");
            E[] newArray=(E[])new Object[array.length+5];

            for (int i=0; i<array.length;i++) {
                newArray[i]=array[i];
            }
            array=newArray;
        }
            array[size]=element;
            empty=false;
            size++;

    }


    public void pop(){
        if(empty==false) {
            array[size]=null;
            size--;
        }else {
            System.out.println("Can't pop an empty stack");
        }

        if(size==0) {
            empty=true;
        }
    }

    public E peek() {
        E element=array[size-1];
        return element;
    }

    public int size() {

        return size;
    }

    public boolean isEmpty() {
        return empty;
    }

}
public class Book {

        String title;
        String author;
        String category;


        public Book(String title, String author, String category) {

        }

        public String getCategory() {
            return category;
        }

        public String toString() {
            return title + " by " + author +", " + "category:" + category;
        }


}