qsort C++ VS2013 leetcode

class Solution {
private:
    static int compare(const void * a, const void * b)
    {
        return (*(int*)a - *(int*)b);
    }

public:
int majorityElement(vector<int>& nums) {
    qsort(&nums[0], nums.size(), sizeof(int), &Solution::compare);
    return nums[nums.size() / 2];
}
};