Fractional kanpsack

//{ Driver Code Starts
#include <bits/stdc++.h>
using namespace std;

struct Item{
    int value;
    int weight;
};

bool cmp(Item  a , Item b){
    double acmp = ((double)(a.value))/((double)(a.weight));
    double bcmp = ((double)(b.value))/((double)(b.weight));
    return acmp > bcmp ;
}

class Solution
{
    public:
    //Function to get the maximum total value in the knapsack.
    double fractionalKnapsack(int w, Item arr[], int n)
    {

        if(n == 1 && arr[0].weight<w)return (double)arr[0].value;
        sort(arr , arr+n , cmp);
        double profit= 0;
        for(int a=0;a<n;a++){
            if((arr[a].weight) <= w){profit += arr[a].value;w = w- arr[a].weight;}
            else {
                profit += w * ((double)arr[a].value/(double)arr[a].weight);
                w=0;
                break;

            }
        }
        return profit;
    }

};