import java.util.*;

public class TestStack {

public static void main (String[] args) {

Stack<Integer> st = new Stack<Integer>();

st.push(1);

st.push(3);

st.push(5);

st.push(7);

while (!st.empty()) {

System.out.println(st.peek());

st.pop();

}

//Better implentation:

Deque<Integer> st2 = new ArrayDeque<>();

st2.push(1);

st2.push(3);

st2.push(5);

st2.push(7);

System.out.println("Iterating the ArrayDeque:");

// Output should be "7, 5, 3, 1,"

for(Iterator<Integer> iter = st2.iterator(); iter.hasNext();) {

System.out.print(iter.next() + ", ");

}

System.out.println("");

System.out.println("Iterating the ArrayDeque reversely:");

// Output should be "1, 3, 5, 7,"

for(Iterator descItr = st2.descendingIterator();descItr.hasNext();) {

System.out.print(descItr.next() + ", ");

}

System.out.println("");

System.out.println("Popping out all the elements:");

while(!st2.isEmpty()) {

System.out.print(st2.pop() + ", ");

}

System.out.println("");

}

}