// ragged arrays
// that is, an array of arrays, where each "sub-array" has different sizes

public class array_ragged0 {
    public static void main(String[] args) {
	
	// two 1-D arrys using initializer lists
	int[] x = {1,2};
	int[] y = {3,4,5};

	// how do you create a 2-D array using arrays x and y?

	//-------------------------------------------------------------------
	// try making the 2-D array first:
	//-------------------------------------------------------------------
	int A[][]=new int[2][3];
	A[0]=x;
	A[1]=y;

	// values inside A:
	// A[0][0]=1, A[0][1]=2
	// A[1][0]=3, A[1][1]=4, A[0][2]=5
	
	// But... is there a value A[0][2]???
	// No! Why? A[0] is a reference to the array x
	// When Java executed the line A[0]=x, the reference to the 
	// 3-element row of A was lost, and a new refernce to x was
	// connected to A[0]

	// Try accessing A[0][2] anyway:
	// System.out.println(A[0][2]);
	// you will see java.lang.ArrayIndexOutOfBoundsException: 2
	//        at array_ragged0.main(Compiled Code)

	//-------------------------------------------------------------------
	// so, you could have formed a 2-D array in other ways
	//-------------------------------------------------------------------
	int[][] B = new int[2][];
	B[0] = x; B[1] = y;         // 1) direct assignment
	B = new int[][] { x, y };   // 2) use anonymous array

	//-------------------------------------------------------------------
	// how should you access all elements since you might not
	// know the size of each sub-array in an array or arrays?
	// --> Use named constants for each array length
	//-------------------------------------------------------------------

	System.out.println("Number of rows of A: " + A.length);
	for(int i = 0; i < A.length; i++)
	    System.out.println("Number of colums of A: " + A[i].length);

	System.out.println("Number of rows of B: " + B.length);
	for(int i = 0; i < B.length; i++)
	    System.out.println("Number of colums of B: " + B[i].length);

	//-------------------------------------------------------------------
	// now, do something useful, like printing out the array values
	//-------------------------------------------------------------------
	// loop from 0 to # of arrays -- think of A.length as # of rows
	   for (int i = 0; i < B.length; i++) {
	       // loop from 0 to length of each sub-array --> 
	       // --> think of B[0].length as the length of each row
	          for (int j = 0; j < B[i].length; j++)
	    	  System.out.print(B[i][j] + " ");
	       System.out.println();
	}

    }
}

/* output:
Number of rows of A: 2
Number of colums of A: 2
Number of colums of A: 3
Number of rows of B: 2
Number of colums of B: 2
Number of colums of B: 3
1 2 
3 4 5 
*/