Question

JAVA Implement a MyQueue class which implements a queue using two stacks. private int maxCapacity = 4; private Stack stack1; private Stack stack2; Note: You can use library Stack but you are not allowed to use library Queue and any of its methods Your Queue should not accept null or empty String or space as an input You need to implement the following methods using two stacks (stack1 & stack2) and also you can add more methods as well: public int size() public void insert(String value) public String remove() private void shiftStacks() public boolean isEmpty() public boolean isFull()

public class MyQueue{
private int maxCapacity = 4;
private Stack<String> stack1;
   private Stack<String> stack2;
  
public MyQueue(){
}
public int size(){
}
public void insert(String value){
}
public String remove(){
}
private void shiftStacks(){
}
public boolean isEmpty() {
}
public boolean isFull(){
}
  
@Override //[QueueSize:Full/Empty:QueueElementsList]
   public String toString(){
       shiftStacks();
       StringBuilder sb = new StringBuilder("[");
       sb.append(this.size()).append(":");
       if(this.isEmpty())
           sb.append("Empty").append(":");
       else if (this.isFull())
           sb.append("Full").append(":");
       while(!isEmpty()){
           sb.append(this.remove());
           if(this.size()!=0) sb.append(", ");
       }
       sb.append("]");
       return sb.toString();
   }   
}

Answer 1

MyQueue.java:

import java.util.Stack;

public class MyQueue{
    private int maxCapacity = 4;
    private Stack<String> stack1;
    private Stack<String> stack2;

    public MyQueue(){
        stack1 = new Stack<>();
        stack2 = new Stack<>();
    }

    public int size(){
        return stack1.size() + stack2.size();
    }

    public void insert(String value){
        if(value == null || value == "" || value == " ")
            return;
        if(stack1.size() == maxCapacity)
            System.out.println("Reached maximum capacity");
        stack1.push(value);
    }

    public String remove(){
        if(stack2.isEmpty()){
            while(!stack1.isEmpty()){
                stack2.push(stack1.pop());
            }
        }
        String popped = stack2.pop();
        if(stack1.isEmpty()){
            while(!stack2.isEmpty()){
                stack1.push(stack2.pop());
            }
        }
        return popped;
    }

    private void shiftStacks(){
//        Stack<String> temp = stack1;
//        stack1 = stack2;
//        stack2 = temp;
    }

    public boolean isEmpty() {
        return stack1.isEmpty();
    }

    public boolean isFull(){
        if(stack1.size() == maxCapacity){
            return true;
        }
        return false;
    }

    @Override //[QueueSize:Full/Empty:QueueElementsList]
    public String toString(){
        shiftStacks();
        StringBuilder sb = new StringBuilder("[");
        sb.append(this.size()).append(":");
        if(this.isEmpty())
            sb.append("Empty").append(":");
        else if (this.isFull())
            sb.append("Full").append(":");
        while(!isEmpty()){
            sb.append(this.remove());
            if(this.size()!=0) sb.append(", ");
        }
        sb.append("]");
        return sb.toString();
    }
}