Question

Question 1
Refer to the operations below:
Add (10 + 5)
Add (4+8)
Add (7*2)
Add (90 – 3)
Print list
Print peek
Remove an item from the list
Print list
1.1 Implement the operations above into a Queue structure called q1.
1.2 Implement the operations above into a Stack structure called s1.

Name your program Question1_1 for the queue structure and Question1_2 for the stack structure

JAVA Language to be used.

Please give step by step explanation on how to save and run the programs

Answer 1

In Java, we have available data structures for queue and stack.

1. Using Queue data structure.

- Create a file named Question1_1.java and add below code into it.

import java.util.*;
public class Question1_1 {
    public static void main(String[] args) {
        
        //We can't create instance of a Queue since it is an interface
        Queue<Integer> q1 = new LinkedList<Integer>();
        
        //Adding elements to the Queue
        //it will add 15
        q1.add(10+5);
        
        //it will add 12
        q1.add(4+8);
        
        //it will add 14
        q1.add(7*2);
        
        //it will add 87
        q1.add(90-3);
        
        //to print a list
        System.out.println("List :"+q1);
       
        //peek() method - it returns the head of queue and null if list is empty
        System.out.println("peek(): "+q1.peek());
        
        //remove() - it will remove first element from queue
        System.out.println("Removed element: "+q1.remove());
        
        //to print a list
        System.out.println("List :"+q1);
    }
}

Save your file and in cmd, go to the directory where you saved your program Question1_1.java

Type javac Question1_1.java and press enter to compile you code. If there is no errors in your code, It will take to next line

Now type java Question1_1.java to run your program and you can see the output on cmd window.

You can refer this screenshots for indentation and output of the code

Output :

2. Using a stack

Create a file named Question1_2.java and add below code into it.

import java.util.*;
public class Question1_2 {
    public static void main(String[] args) {
        
        //create instance of a Stack as s1
        Stack<Integer> s1 = new Stack<Integer>(); 
        
        //Adding elements to the Stack using push method
        //it will add 15
        s1.push(10+5);
        
        //it will add 12
        s1.push(4+8);
        
        //it will add 14
        s1.push(7*2);
        
        //it will add 87
        s1.push(90-3);
        
        //to print a list
        System.out.println("List :"+s1);
       
        //peek() method - it returns the top of stack and null if stack is empty
        System.out.println("peek(): "+s1.peek());
        
        //pop() - it will remove top element from stack
        System.out.println("Removed element: "+s1.pop());
        
        //to print a list
        System.out.println("List :"+s1);
    }
}

Save your file and in cmd, go to the directory where you saved your program Question1_2.java

Type javac Question1_2.java and press enter to compile you code. If there is no errors in your code, It will take to next line

Now type java Question1_2.java to run your program and you can see the output on cmd window.

You can refer this screenshots for indentation and output of the code

Output :

NOTE : make sure that you have set path variable to run java code in your system.