i have 2 "errors term does not evaluate to a function tacking 2 arguments" in line 64

Code:

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#include "Bibleoteca.h"
#include<list>
#include<vector>
#include<algorithm>
#include<iostream>
using namespace std;

void Bibleoteca::Adauga(Carte book)
{
        books.push_back(book);
        cout << endl;
}
void Bibleoteca::Afis()
{
        for (auto& elem : books)
        {

                elem.Print();
       
        }
}
void Bibleoteca::cauta_Titlu(string title)
{
        for (auto  &elem : books)
        {
                if (elem.titlu == title)
                {
                        elem.Print();
                }
        }
}


//void Bibleoteca::caut_Editura(string editura)
//{
//        auto reult = find(begin(books), end(books), editura);
//        if (reult != end(books))
//        {
//                this->Afis();
//        }
//        else
//        {
//                cout << "librarie nu contine" << endl;
//        }
//}

Carte * Bibleoteca::caut_ISBN(string ISBN)
{
        for (auto &elem : books)
        {
                if (elem.ISBN == ISBN)
                {
                        return &elem;
                }
        }
        return nullptr;
}
void Bibleoteca::unic_ISBN(string ISBN)
{

        auto count =  unique(books.begin(), books.end(),books.size());

}

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1. Please use COODE tags while posting code snippets.
2. Where is your "line 64"?

Code:

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auto count = unique(books.begin(), books.end(),books.size());

---

If this is using std::unique()? If yes, then its 3rd param is wrong. Either don't have one or it needs to be binary predicate.
See auto count = unique(books.begin(), books.end(),books.size());

If this is not std::unique(), what's the implementation/declaration?