Question

You may not use the java.util.Stack class.
You may not use the java.util.Queue class.
Ex1: Write a program that converts a decimal to binary using a stack.

My professor gave me this question to code, is this even possible? if it is can someone code it, in java.

Answer 1

We can implement the stack using arrays.

Code:

import java.util.*;
public class Main
{
    static int stack[]=new int[100];
    static int top=-1;
    /*Implementation of push */
    public static void push(int b)
    {
        top=top+1;
        stack[top]=b;
    }
    /*Implementation of pop */
    public static int pop()
    {
        int b=stack[top];
        top=top-1;
        return (b);
    }
    
        public static void main(String[] args) 
        {
                Scanner sc=new Scanner(System.in);
                System.out.print("Enter decimal number::");
                int n=sc.nextInt();
                int r;
                /*If decimal number is 0 the directly push 0*/
                if(n==0)
                {
                    push(0);
                }
                else
                {
                    while(n>0)
                    {
                        r=n%2;
                        push(r);
                        n=n/2;
                    }
                }
                System.out.print("The binary number is::");
                while(top>=0)
                {
                    System.out.print(pop());
                }
        }
}

Screenshots: