Product of Array Except Self

Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].

Solve it without division and in O(n).

For example, given [1,2,3,4], return [24,12,8,6].

Follow up:
Could you solve it with constant space complexity? (Note: The output array does not count as extra space for the purpose of space complexity analysis.)

 

class Solution {

public:

    vector<int> productExceptSelf(vector<int>& nums) {

        vector<int> res(nums.size(),1);

        

        int i;

        for(i=1;i<nums.size();i++)

        {

            res[i]=res[i-1]*nums[i-1];

        }

        int right=1;

        for(i=nums.size()-1;i>=0;i--)

        {

            res[i]*=right;

            right*=nums[i];

        }

        return res;

    }

};