The only way without a while loop and no method I can think of is use switch with every possible variation of the four digit binary which is 15.
Here is the starter code:
import java.util.Scanner; public class MyClass { public static void main(String args[]) { Scanner sc = new Scanner(System.in); int digit = sc.nextInt(); switch(digit) { case 0000: System.out.println("0"); break; case 0001: System.out.println("1"); break; case 0010: System.out.println("2"); break; case 0011: System.out.println("3"); break; case 0100: System.out.println("4"); break;
… (fill in other cases)
} } }
Use this link: https://www.electronics-tutorials.ws/binary/bin_3.html
There might be a better way, but without loops or methods this is all I got.