Question

Using only stack operations push() and pop() reverse the contents of a stack in the Java programming language

Answer 1

CODE

import java.util.Stack;

public class Main {

public static void main(String[] args)

{

Stack<String> stack = new Stack<String>();

stack.push("a");

stack.push("b");

stack.push("c");

stack.push("d");

stack.push("e");

stack.push("f");

ReverseStack(stack);

System.out.println(stack);

}

public static <T> void ReverseStack(Stack<T> stack)

{

for (int i = 0; i < stack.size(); i++)

{

T targetElement = stack.pop();

ReverseStackStep(stack, stack.size() - i, 0, targetElement);

}

}

public static <T> void ReverseStackStep(Stack<T> stack, int limit, int currentLevel, T targetElement)

{

if (currentLevel == limit)

{

stack.push(targetElement);

}

else

{

T element = stack.pop();

ReverseStackStep(stack, limit, currentLevel + 1, targetElement);

stack.push(element);

}

}

}