[LinkedIn]find balance (equilibrium) point (index) in an array (unsorted)

Code From Here (g4g)

/**
1) Initialize leftsum  as 0
2) Get the total sum of the array as sum
3) Iterate through the array and for each index i, do following.
    a)  Update sum to get the right sum.  
           sum = sum - arr[i]  sum is now right sum
    b) If leftsum is equal to sum, then return current index. 
    c) leftsum = leftsum + arr[i] 
4) return -1 
**/

int equilibrium(int arr[], int n)
{
   int sum = 0;      // initialize sum of whole array
   int leftsum = 0; // initialize leftsum
   int i;

   /* Find sum of the whole array */
   for (i = 0; i < n; ++i)
        sum += arr[i];

   for( 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;
}