Static String Return Type

Hello,

I have an array interface and I should write the methods for them,I have a question in the following method.
I should write a method String toString(int[] arr) that returns a string which, if printed, provides a niprint out of the array content. Used as:
int n = {3,4,5,6,7};
String str = Arrays.toString(n);
System.out.println("n = " + str);

I have written my method like this :

Code:

---

static String toString(int[] arr)
        {
                System.out.print("\n"+ "All the values in the array are: " );
                int i;
                String array = null;
                for ( i = 0; i < arr.length; i++ )
                {
                        array=Integer.toString(arr[i]);
                        System.out.print(" "+ array);
                }
                return " "+ array;
        }

---

& the return type return NULL !I would like to know what I can I call as a return type.

Thanks all in advance.

Di you call the method with array that has values.

Yes Actually Like this
int[] array = new int[] {1,2,3,10,5};
Arrays.toString(array);

& It prints :
All the values in the array are: 1 2 3 10 5
Which is correct but It's the System.out.println that shows this line if I remove it wont show anything I mean the return " "+ array; won't return anything !

You do realise that this

Code:

---

array=Integer.toString(arr[i]);

---

results in only the last element being "saved" in the String, right?

Yes you are right!But I couldn't find a better way to implement that method.

Quote:

---

Originally Posted by Java_Developer

..
Which is correct but It's the System.out.println that shows this line if I remove it wont show anything I mean the return " "+ array; won't return anything !

---

The println won't change the value that is returned by the method.

Quote:

---

Originally Posted by Java_Developer

Yes you are right!But I couldn't find a better way to implement that method.

---

+= maybe?

& then I will get the following return type which is totally wrong :

All the values in the array are: null1 null12 null123 null12310 null123105

Code:

---

String array = "";
...
array += " " + Integ....
System.out.println(array);//this is obviously only debug

---

You mean like this:

Code:

---

static String toString(int[] arr)
        {
                System.out.print("\n"+ "All the values in the array are: " );
                int i;
                String array = "";
                for ( i = 0; i < arr.length; i++ )
                {
                        array+=" " + Integer.toString(arr[i]);
                       
                }
                return array;

---

But still array won't return anything :(

Show the "calling" code. You probably doing something wrong outside of this method.

The calling code is simple one :

int[] array = new int[] {1,2,3,10,5};
Arrays.toString(array);

That has nothing to do with the method you just wrote, and you are not storing the result of that anywhere.

Yes and the test is like :
String test=Arrays.toString(array);
System.out.print(test);

and it will show the last element in the array just 5 !

Read Masi's reply #9 above again.

So, you've written your own class Arrays? You do know that there is already an Arrays class, right?

Yes I know and then testing this class with Junit .

Thanks for helping me,the problem solved now :)