Activity Selection

#include<iostream>
#include<algorithm>

using namespace std;

struct data
{
    int start,nd,index;

}arr[1000];

bool cmp(data lhs,data rhs)
{
    return lhs.nd<rhs.nd;
}

int main()
{
    int koyta_activity,i,index,counter,nd_time;

    while(cin>>koyta_activity)
    {

        for(i=1;i<=koyta_activity;++i)
        {
            cin>>arr[i].start>>arr[i].nd;

            arr[i].index=i;
        }

        sort(arr+1,arr+koyta_activity+1,cmp);

        nd_time=0;

        counter=0;

        cout<<endl;
        cout<<endl;

        for(i=1;i<=koyta_activity;++i)
        {
            if(nd_time<=arr[i].start)
            {
                cout<<arr[i].index<<" --> "<<arr[i].start<<" "<<arr[i].nd<<endl;

                nd_time=arr[i].nd;

                counter++;
            }
        }

        cout<<endl;

        cout<<"Total number of selected activities is "<<counter<<endl<<endl;
    }
    return 0;
}