public Node[] stack; // this is supposedly my array
               stack = new Node[size2]; // this is what i had to initialize the size of the stack, in which the user prompts.

 
public class MStack implements Stack{
 
	public Node top;
	public Node[] stack;
	public int T[];
	public int B[];
	public  int oldT[];
	public static int i;
	int size2;
	int noOfStack2;
 
 
	class Node{
		Object info;
		Node link;
	}
 
	public MStack(){
 
	}
 
	public MStack(int size, int noOfStack){
		size2= size;
		noOfStack2 = noOfStack;
		stack = new Node[size2];
		T = new int[noOfStack2 + 1];
		B = new int[noOfStack2 + 1];
		oldT = new int[noOfStack2 + 1];
		for (int i = 0; i < noOfStack2; i++){
			B[i]= (int)Math.floor(size2/noOfStack2) * i -1;
			T[i] = B[i];
			B[noOfStack2] = size2- 1;
		}B[noOfStack2] = size2 - 1;
	}
 
	public Object top(int i){
		return top.info;
	}
 
	public void push(String item,int i ) {
		if (T[i]== B[i+1]){
				System.out.println("Stack"+ i + "is full.");
		}else{
			stack[i] = new Node();
			stack[i].info = item;
			stack[i].link = top;
			top =stack[i];
			System.out.println("You have pushed " + item + " into stack!");
			T[i]++;
		}
	}
 
	public Object pop(int i ){
		Node temp;
		if (isEmpty(i))
			throw new StackException("Stack underflow.");
			temp = top;
			top = top.link;
		return temp.info;
	}
 
	public boolean isEmpty(int i){
		boolean ques = false;
		if(T[i] == B[i]){
			ques = true;
		}
		return ques;
 
	}
 
	public int size(int i){
		int size[]= new int[i];
		size[i] = T[i] - B[i] ;
		return size[i];
	}
 
}

import java.io.*;
 
public class BookShelf extends MStack {
 
		public  InputStreamReader ir = new InputStreamReader(System.in);
		public  BufferedReader bf = new BufferedReader(ir);
		public  BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
		public  MStack bookShelf;
		public  int size;
		public  int shelf;
 
		public static void main (String []args) throws IOException{
			new BookShelf();
		}
 
		public BookShelf()throws IOException{
			super();
			options();
		}
 
		public void options()throws IOException{
			System.out.println("What size do you want your bookshelf to be?Integers only.:");
			size =	Integer.parseInt(in.readLine());
			System.out.println("How many shelves do you want your bookshelf to have?:");
			shelf = Integer.parseInt(in.readLine());
			bookShelf = new MStack(size, shelf);
			System.out.println("You have now a book shelf with " +size+ " capacity and " +shelf+ " shelves" );
			try{
				do{
					System.out.println("\nPlease choose from below. Use numbers to choose.");
					System.out.println("1. Place book on shelf");
					System.out.println("2. Retrieve book from shelf");
					System.out.println("3. Show items on shelf");
					System.out.println("4. Exit");
					int choice = Integer.parseInt(in.readLine());
					if  (choice == 1){
						try{
							System.out.println("Which shelf do you want to place a book?(Integers only");
							int placement = Integer.parseInt(in.readLine());
							int i;
							if(placement == 1){
								i = 0;
								System.out.println("Enter element:");
								String item = bf.readLine();
								bookShelf.push(item,i);
							}if(placement == 2){
								i = 1;
								System.out.println("Enter an element:");
								String item = bf.readLine();
								bookShelf.push(item,i);
							}if(placement == 3){
								i = 2;
								System.out.println("Enter an element:");
								String item = bf.readLine();
 
								bookShelf.push(item,i);
						}
						}catch(ArrayIndexOutOfBoundsException e){
 
							}
					}else if (choice == 2){
						System.out.println("Which shelf do you want to retrieve a book? Integers only.");
						int choice2 = Integer.parseInt(in.readLine());
						try{
							switch (choice2){
								case 1 : if (bookShelf.isEmpty(choice2)) {
											System.out.println("Shelf is empty");
											break;
										}else{
											System.out.println("Item " + bookShelf.pop(choice2)+ " is retrieved.");
											break;
										}
								case 2 : if (bookShelf.isEmpty(choice2)) {
											System.out.println("Shelf is empty");
											break;
										}else{
											System.out.println("Item " + bookShelf.pop(choice2)+ " is retrieved.");
											break;
										}
								case 3 : if (bookShelf.isEmpty(choice2)) {
											System.out.println("Shelf is empty");
											break;
										}else{
											System.out.println("Item " + bookShelf.pop(choice2)+ " is retrieved.");
											break;
										}
								}
						}catch(NullPointerException e){
 
						}
					}else if (choice == 3){
						for (int i = 0; i <= shelf; ++i) {
							if (!isEmpty(i)){
								System.out.println("shelf #" + i + ": " + bookShelf.pop(i));
							}else{
								System.out.println("shelf #" + i + ": is empty.");
								break;
							}
						}
 
					}else if ( choice == 4){
						System.out.println("You have exited. Thank you!");
						break;
					}
			}while (true);
		}catch(IOException e){}
	}
 
 
}