import java.util.Random;

public class TestAStack {

    public static void main(String[] args) {
    	
    	// when constructing a stack it needs a length
    	int length = 10;
        AStack<Integer> arrayStk = new AStack<Integer>(length);
        
        Random rgen = new Random();
        for(int i=0; i< length; i++)
        {
            arrayStk.push(new Integer(rgen.nextInt(10) + 1));
        }
        System.out.println(arrayStk);
        
        while(!arrayStk.isEmpty())
        	System.out.println("Poping " + arrayStk.pop());
         
    }
}

public class AStack<T> {

    private T[] stk;
    private int length;//the number of element the stack can store
    private int count;//the number of element the stack is storing
    
    
    public AStack(int len)//create an empty AStack that can store up to len element
    {
        length = len;
        count = 0;
        stk =(T []) new Object[len];//array with empty element
    }
    
    
    public boolean isEmpty()
    {
        return count==0;
    }
    
    public boolean isFull()
    {
        return count == length;
    }
    
    public int size()
    {
        return length;
    }
    
    public T peek()
    {
        if(isEmpty())
        {
            System.out.println("Peek:Stack is empty");
            return null;
        }
        else
            return stk[count--];
    }

    public T pop()
    {
        if(isEmpty())
        {
            System.out.println("Pop:Stack is empty");
            return null;
        }
        else 
            return stk[--count];
    }
    public void push(T item)
    {
    	if(count == length) {
    		System.out.println("Stack is full");
    		return;
    	}
    	System.out.println("Inserting " + item + " at [" + count + "]");
    	stk[count++] = item;
        
    }
    @Override
    public String toString()//return the string element
    {
        String s = "[";
        for(int i = 0; i <count; i++)
        {
            if(i != 0)
            	s += ", ";
            s = s + stk[i];// [value1,value2,....]
        }
        
        s +="]";
        return s;
    }
    
}