// create array using 1D arrays

public class aoa0_blanks {
    public static void main(String args[]) {

        // create 2x2 array with default values:



        // create array $r0$ and store values 1 and 2:



        
        // create array $r1$ and store values 3 and 4:



        
        // store refs to arrays $r0$ and $r1$ as 
        // 1st and 2nd elements of array $a$:




        // Use $a[i][j]$ to access elements:

           for (_______ ; ___________ ; ____ ) {        // "rows"

	      for (_______ ; ___________ ; ____ )       // "cols"

		   System.out.print( ____________ ) ;   // element

	      _________________________________ ;       // skip line between rows
           }

    } // method main

} // class aoa0_blanks

/* Output
1 2 
3 4
*/