Why is eclipse asking me to change the type of this int variable to int[]?

Question

I was running a test code to verify my friend's argument that arrays couldn't be passed in the form of an actual array instead of the name of the array variable. Here it is:

 public class test 
{
int sumarr( int[] arr)
{
    int sum=0;

    int length = arr.length;

    for(int i = 0;i<length;i++)
    {
        sum+=arr[i];
    }
    return sum;
}

public static void main(String[] args)
{
    int sum = sumarr({1,2,3});
    System.out.println(" Sum is "+sum);

}
}

However, eclipse says that the line int sum=sumarr({1,2,3}) exhibits type mismatch and that i should change the type from int to int[]. How is it possible when sumarr returns an int value?

Answer 1

{1,2,3} is not an Array initialization. You should add new int[], like:

int sum = sumarr(new int[] { 1,2,3 });

Answer 2

There are few mistakes in your code:

1. you are trying to use non-static method in static one without instance so maybe consider changing your method to static one like

   static int sumarr(int[] arr) {...}
   

2. you are not passing array of integers because {1,2,3} can be used only with declaration of variable like

   int[] someArray = {1,2,3}; 
   

   Without this declaration part compiler can't assume correct type of array which should be created here (it could be array of longs, floats and any other type of numbers).
   To solve that you need to provide actual type of array you want to use by

   new int[]{1,2,3};
   ^^^^^^^^^
   

   so change your code to

   int sum = sumarr(new int[]{1,2,3});