<script>

// program to find equilibrium

// index of an array

 function equilibrium(arr, n)

{

    sum = 0; // initialize sum of whole array

    leftsum = 0; // initialize leftsum

    /* Find sum of the whole array */

    for (let i = 0; i < n; ++i)

        sum += arr[i];

    for (let i = 0; i < n; ++i)

    {

        sum -= arr[i]; // sum is now right sum for index i

        if (leftsum == sum)

            return i;

        leftsum += arr[i];

    }

    /* If no equilibrium index found, then return 0 */

    return -1;

}

// Driver code

arr =new Array(-7, 1, 5, 2, -4, 3, 0);

n=arr.length;

document.write("First equilibrium index is " + equilibrium(arr, n));

// This code is contributed by simranarora5sos

</script>