// purpose: demonstrate default matrix initialization

public class MatrixDefault {

	public static void main( String[] args ) {
		int[][] a = new int[ 4 ][ 4 ];

		int rows = a.length;
		int columns = a[0].length;

		System.out.println( "a before manipulation" );
		System.out.println( "_______________________" );
		for ( int r = 0; r < rows; ++r ) {
			// process row r
			for ( int c = 0; c < columns; ++c ) {
				// process the element in column c of row r
				System.out.print( a[ r ][ c ] + " " );
			}
			System.out.println();
		}

		System.out.println();
		System.out.println();

		for ( int r = 0; r < rows; ++r ) {
			// process row r
			for ( int c = 0; c < columns; ++c ) {
				// process the element in column c of row r
				a[ r ][ c ] = r + c;
			}
		}

		System.out.println( "a after manipulation" );
		System.out.println( "_______________________" );
		for ( int r = 0; r < rows; ++r ) {
			// process row r
			for ( int c = 0; c < columns; ++c ) {
				// process the element in column c of row r
				System.out.print( a[ r ][ c ] + " " );
			}
			System.out.println();
		}
	}
}