LeetCode:Single-Number

Given an array of integers, every element appears twice except for one. Find that single one.
Note:
Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

i
class Solution {
public:
    int singleNumber(int A[], int n) {
       int result = A[0];
       for(int i=1;i<n;++i)
         {
            result = result^A[i];  
         }
        return result;
    }
};