Water Bottles

<-E 1518> Water Bottles

class Solution {
public:
    int numWaterBottles(int numBottles, int numExchange) {
        int s = numBottles,l = 0,p;
        while((numBottles / numExchange) > 0)
        {
            p = (numBottles / numExchange);
            l = (numBottles % numExchange);
            s += p;
            numBottles = p + l;
        }
        return s;
    }
};