Fibonacci using do-while

FiboDoWhile.java

import java.util.Scanner;
 
public class FiboDoWhile {
    public static void main(String []args)
    {
        Scanner keyboard = new Scanner(System.in);
        System.out.print("Input n (integer): ");
        
        int n = keyboard.nextInt();
        int n_2 = 0, n_1 = 1, a = 0;
        int fibSeq = 0;
        if (n == 0) System.out.print(n_2 + " ");
        else if (n == 1) System.out.print(n_2 + " " + n_1 + " ");
        else {
            System.out.print(n_2 + " ");
            do {
                fibSeq = n_1 + n_2;
                n_1 = n_2;
                n_2 = fibSeq;
                System.out.print(fibSeq+" ");
                a++;
            } while(a<n);
        } 
        // output: 0 1 1 2 3 5 ....
    }
}