Reference types - Data Structures and Problem Solving Using Java - page 46

figure 2.9
Printing a two-
dimensional array

1 public class MatrixDemo
2 {
3 public static void printMatrix( int [ ][ ] m )
4 {
5 for( int i = 0; i < m.length; i++ )
6 {
7 if( m[ i ] == null )
8 System.out.println( "(null)" );
9 else
10 {
11 for( int j = 0; j < m[i].length; j++ )
12 System.out.print( m[ i ][ j ] + " " );
13 System.out.println( );
14 }
15 }
16 }
17
18 public static void main( String [ ] args )
19 {
20 int [ ][ ] a = { { 1, 2 }, { 3, 4 }, { 5, 6 } };
21 int [ ][ ] b = { { 1, 2 }, null, { 5, 6 } };
22 int [ ][ ] c = { { 1, 2 }, { 3, 4, 5 }, { 6 } };
23
24 System.out.println( "a: " ); printMatrix( a );
25 System.out.println( "b: " ); printMatrix( b );
26 System.out.println( "c: " ); printMatrix( c );
27 }
28 }

2.4.6 enhanced for loop

Java 5 adds new syntax that allows you to access each element in an array or
ArrayList , without the need for array indexes. Its syntax is

for( type var : collection )
statement

Inside statement , var represents the current element in the iteration. For
instance, to print out the elements in arr , which has type String[] , we can
write:

for( String val : arr )
System.out.println( val );