// CSE 143, Winter 2010, Marty Stepp
// This program demonstrates a recursive printBinary method that 
// prints the binary representation of an integer.
//
// We also wrote a recursive pow method today which is included below.

public class Binary {
    public static void main(String[] args) {
        printBinary(4);       // 100
        System.out.println();
        printBinary(12);      // 1100
        System.out.println();
        printBinary(21);      // 10101
        System.out.println();
        printBinary(42);      // 101010
        System.out.println();
        printBinary(69743);   // 10001000001101111
        System.out.println();
    }
    
    // Prints the binary representation of the given integer.
    // For example, printBinary(42) prints 101010.
    // Precondition: n >= 0
    public static void printBinary(int n) {
        if (n <= 1) {
            System.out.print(n);
        } else {
            // n >= 2
            printBinary(n / 2);
            printBinary(n % 2);
        }
    }

    // printBinary(???);
    
    // 42 => 101010
    //            0
    
    // 21 => 10101
    
}