In this tutorial, we will write a java program to convert decimal to binary without using array. Before that, you must have knowledge of the following topics in java.
Binary number
The binary numbers are based on 0 and 1, so it is a base 2 number. They are the combination of 0 and 1. For example, 1001, 110101, etc.
Decimal Number
These are the numbers with a base of 10, which ranges from 0 to 9. These numbers are formed by the combination of 0 to 9 digits such as 24, 345, etc.
Here is the chart where for the equivalent value of decimal and binary numbers.

Example:
Input: 5
Output: 101
Input: 7
Output: 111
Now let us go through a program for the conversion of decimal to binary in java using a while loop.
Java Program to convert Decimal to Binary using while loop
import java.util.Scanner;
public class Main
{
public static void main(String[] args)
{
int i = 1, decimal, binary = 0, rem;
Scanner sc = new Scanner(System.in);
System.out.println("Enter a decimal number: ");
decimal = sc.nextInt();
while (decimal != 0)
{
rem = decimal % 2;
binary += i * rem;
decimal /= 2;
i *= 10;
}
System.out.println("Equivalent Binary Value: " + binary);
}
}
Output:
Enter a decimal number:
10
Equivalent Binary Value: 1010