Lambda used as nested functions.

Element.cpp

#include "Element.hpp"

#include <vector>
#include <string>


size_t count_uniques(const std::vector<SElement> v)
{
    size_t c = 0;
    bool found;

    auto compare = [&v](int i, int j) -> int {
                       if (v[i].e2 == v[j].e2)
                           return 0;
                       else if (v[i].e1 != v[j].e1)
                           return v[j].e1 - v[i].e1;
                       else
                           return v[j].e2 - v[i].e2;
                   };
    
    for (size_t i = 0; i < v.size(); ++i) {
        found = false;
        for (size_t j = 0; j < i; ++j) {
            if (compare(i, j) == 0) {
                found = true;
                break;
            }
        }
        if (!found) ++c;
    }
    return c;    
}

Element.hpp

#ifndef ELEMENT_H
#define ELEMENT_H

#include <string>
#include <vector>

struct SElement
{
    std::string s;
    int e1;
    int e2;
};


size_t count_uniques(const std::vector<SElement> v);

#endif

testElement.cpp

#include "Element.hpp"

#include <iostream>
#include <vector>


int main()
{   
    std::vector<SElement> s1{{"zak", 2, 0},
			     {"mac", 3, 1},
			     {"abc", 4, 2},
			     {"zak", 5, 0}};

    std::cout << count_uniques(s1) << "\n";
    
    return 0;
}