Question

JAVA QUESTION 2.One use of a Stack is to reverse the order of input.

Write a complete method that reads a series of Strings from the user. The user enters "end" to stop inputting words. Then, output the Strings in reverse order of how they were entered. Do not output the String “end”.

Use a stack to accomplish this task. Invoke only the methods push, pop, peek, and isEmpty on the stack object.

Here is an example of how the program would run (user input in blue):

Enter a word or 'end' to quit: Hello

Enter a word or 'end' to quit: Java

Enter a word or 'end' to quit: World

Enter a word or 'end' to quit: end

You entered (in reverse):

World

Java

Hello

Answer 1

import java.util.Scanner;
import java.util.Stack;

public class StackReverse {

    public static void main(String[] args) {
        Stack<String> strings = new Stack<>();
        Scanner in = new Scanner(System.in);
        String str;
        while (true) {
            System.out.print("Enter a word or 'end' to quit: ");
            str = in.next();
            if(str.equals("end")) {
                break;
            }
            strings.push(str);
        }
        System.out.println("You entered (in reverse):");
        while (!strings.isEmpty()) {
            System.out.println(strings.pop());
        }
    }

}

​

Enter a word or 'end' to quit: Hello Enter a word or 'end' to quit: Java Enter a word or 'end' to quit: World Enter a word or 'end' to quit: end You entered (in reverse): World Java Process finished with exit code 0