Enhanced for Loop(for Arrays)

[asha ganapathy]

I wrote this piece of code to print the values of a two dimensional array (after i reffered from K&B book page no.339)
class test{
public static void main(String[] args){
int [][] a = {{1,2,3},{4,5,6},{7,8,9}};
for(int[] n : a)
System.out.println(n);

}
}
But the result i get are not the elements of the array,
it looks like [I@187c6c7
Can anyone explain why am i getting these kind of errors?

[camilo lopes]

you have a bidimensional Array, or either, an Array inside of another Array, entao it prints the value of the object and nao the elements.

[asha ganapathy]

But in the book it says
int [][] twoDee ={{1,2,3},{3,4,5},{5,6,7}};
for(int[] n :twoDee);//loop thru the array of arrays

now how do i print the elements of the array twoDee?

[camilo lopes]

if you to want yes.

  for(int[] n :twoDee)
System.out.println(n[0]);  

[John Bartlett]

Hi,

If you want to print out the entries of -

int [][] twoDee ={{1,2,3},{3,4,5},{5,6,7}};

you would have to do this;

for (int[] outer : twoDee) {
   for (int value : outer) {
       System.out.println(value);
   }
}

John

[asha ganapathy]

oh ok i got it..
thanks a lot, so if i have to print the full array then i can say
System.out.println(n[0]+" "+n[1]+" "+n[2]);

[marc weber]

Originally posted by asha ganapathy:
...the result i get are not the elements of the array, it looks like [I@187c6c7...

Actually, you are getting the elements of the array.

Remember, in Java, multi-dimensional arrays are really just arrays that contain other arrays. When you say for(int[] n : a), this means for each int array (referenced by n) that is an element of the array a. So when you print n, you get a String representation of the array itself (which is an object) -- not the contents of that array.

(In this case, the String representation uses the left bracket "[" to indicate an array, "I" to indicate the type of array as int, followed by a memory address.)

If you want to print the contents of this array (n), you will need to iterate through the elements of n. And since this is a multi-dimensional array (arrays within arrays), that's where nested loops come in. In psuedo code (lacking the iteration details)...

for(each [I]int array[/I] n in a) {
  for(each [I]int[/I] x in n) {
    System.out.println(x);
  }
}