Given an array of integers, every element appears twice except for one. Find that single one.

class Solution {
//using xor bit manipulation
public:
    int singleNumber(int A[], int n) {
        // Note: The Solution object is instantiated only once and is reused by each test case.
        int res = 0;
        for(int i = 0; i < n; ++i)
            res ^= A[i];
        return res;
    }
};

single number i