Multiset with custom < operator - problem with iterators

[orzeech]

Hi everyone!

I have a following problem:

#include<iostream>
#include<set>

using namespace std;

struct punkt
{
       int x;
       int y;
    
};

struct porownaj_x {
  bool operator() (const punkt& lhs, const punkt& rhs) const
  {return lhs.x<rhs.x;}
};

struct porownaj_y {
  bool operator() (const punkt& lhs, const punkt& rhs) const
  {return lhs.y<rhs.y;}
};

int main()
{
    

    int z;
    cin >> z;

    int a,b;
    punkt zabytki[z];
    for (int i=0; i<z; i++)
    {
    cin >> a >> b;
    //tab[a][b]=1;
    zabytki[i].x=a; 
    zabytki[i].y=b;
    }
    
        
    multiset<punkt,porownaj_x> sx;
    multiset<punkt,porownaj_y> sy;

    for (int i=0; i<z; i++)
    { sx.insert(zabytki[i]);
      sy.insert(zabytki[i]);}

   multiset<punkt, porownaj_x>::iterator itt;

int ub = 10;
for (itt=sx.upper_bound(ub); itt!=sx.end(); itt++)
    cout << " " << (*itt).x << " " << (*itt).y;
cin.get();
cin.get();
return 0;
}

Compiler returns an error: 51 no matching function for call to `std::multiset< punkt, porownaj_x, std::allocator< punkt> >::upper_bound( int&)'

Multisets are working perfectly fine but upper_bound and lower_bound iterators aren't:( What is wrong in the code?

[weaknessforcats]

Your multiset has punkt as the key.

multiset<punkt,porownaj_x> sx;

That means your iterator needs a punkt as a key. However, you are using ub which is an int. A punkt and an int are different types.Hence the compiler error.

[boxfish]

I think it's because you're passing an int to the upper_bound function. You have to give it an object of type punkt, its key type. I don't actually know what a multiset is; I just looked it up here.

[orzeech]

Your multiset has punkt as the key.

multiset<punkt,porownaj_x> sx;

That means your iterator needs a punkt as a key. However, you are using ub which is an int. A punkt and an int are different types.Hence the compiler error.

Thank you very very much for the quick reply!!! :)