upper_bound and lower_bound in vector and array

upper_bound and lower_bound in vector and array

 #include<bits/stdc++.h>

using namespace std;

int main()

{

    int n,r;

    cin>>n;

    int a[n];

    for(int i=0;i<n;i++)cin>>a[i];

    sort(a,a+n);

    int *ptr=lower_bound(a,a+n,6);

    if(ptr==a+n)cout<<"NOT Found\n";

    else

    cout<<*ptr<<endl;

    int *it1=upper_bound(a,a+n,6);

   if(it1==a+n)cout<<"NOT Found\n";

    else

    cout<<*it1<<endl;

    vector<int> v;

    cin>>r;

    for(int i=0;i<r;i++)

    {

        int a;

        cin>>a;

        v.push_back(a);

    }

    sort(v.begin(),v.end());

    auto its1=lower_bound(v.begin(),v.end(),5);

    if(its1==v.end())cout<<"NOT FOUND\n";

    else cout<<*its1<<endl;

    auto its2=upper_bound(v.begin(),v.end(),5);

    if(its2==v.end())cout<<"NOT FOUND\n";

    else cout<<*its2<<endl;

    return 0;

}