Array Question

[thejaka samarakoon]

class PassA 
{
    public static void main(String [] args) 
    {
        PassA p = new PassA();
        p.start();
    }

    void start() 
    {
        long [] a1 = {3,4,5};
        long [] a2 = fix(a1);
        System.out.print(a1[0] + a1[1] + a1[2] + " ");
        System.out.println(a2[0] + a2[1] + a2[2]);
    }

    long [] fix(long [] a3) 
    {
        a3[1] = 7;
        return a3;
    }
}

Can somebody explain How the answer to this question becomes" 15 15" ?

[Seetharaman Venkatasamy]

thejaka samarakoon wrote:

    long [] a1 = {3,4,5};
    long [] a2 = fix(a1);
        

    long [] fix(long [] a3) 
    {
        a3[1] = 7;
        return a3;
    }

Can somebody explain How the answer to this question becomes" 15 15" ?

you are passing copy of the reference of a1 to a method called fix, there you are modifying the object array[which referenced by a1] by using the copy of reference a3 then assign to the object array to reference a2. so now a2 and a1 both reference to the existing array object. hence the result.

hope this helps

[Ikpefua Jacob-Obinyan]

The fix() method changes the value of the second element of the array to 7 so you now have

{3,7,5}

Then the println statements displays the total sum of the values of the elements, which is equal to 15 15. If you want individual elements to be displayed then modify the println statement as follows:

System.out.print(a1[0] + " " +  a1[1] + " " + a1[2] + " ");  
System.out.println(a2[0] + " " + a2[1] + " " + a2[2]);  

Output:

3 7 5 3 7 5

I hope this helps

Regards

Ikpefua

[thejaka samarakoon]

Thanks