Language: C++

#include <iostream>
#include <string>
#include <algorithm> 
using namespace std;
int main(){
    int n;
    cin >> n;
    vector<int> a(n);

    for(int i=0;i<n;i++){
        cin >> a[i];
    }

    sort(a.begin(),a,end());

    int count=0;
    for(int i=0;i<n;i++){
        if(a[i]!=a[i-1]){
            count++;
        }
    }

    cout << count << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:5: error: 'vector' was not declared in this scope
    8 |     vector<int> a(n);
      |     ^~~~~~
a.cc:4:1: note: 'std::vector' is defined in header '<vector>'; this is probably fixable by adding '#include <vector>'
    3 | #include <algorithm>
  +++ |+#include <vector>
    4 | using namespace std;
a.cc:8:12: error: expected primary-expression before 'int'
    8 |     vector<int> a(n);
      |            ^~~
a.cc:11:16: error: 'a' was not declared in this scope
   11 |         cin >> a[i];
      |                ^
a.cc:14:10: error: 'a' was not declared in this scope
   14 |     sort(a.begin(),a,end());
      |          ^
a.cc:14:25: error: no matching function for call to 'end()'
   14 |     sort(a.begin(),a,end());
      |                      ~~~^~
In file included from /usr/include/c++/14/bits/range_access.h:36,
                 from /usr/include/c++/14/string:53,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/initializer_list:99:5: note: candidate: 'template<class _Tp> constexpr const _Tp* std::end(initializer_list<_Tp>)'
   99 |     end(initializer_list<_Tp> __ils) noexcept
      |     ^~~
/usr/include/c++/14/initializer_list:99:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:74:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.end()) std::end(_Container&)'
   74 |     end(_Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:74:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:85:5: note: candidate: 'template<class _Container> constexpr decltype (__cont.end()) std::end(const _Container&)'
   85 |     end(const _Container& __cont) -> decltype(__cont.end())
      |     ^~~
/usr/include/c++/14/bits/range_access.h:85:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:106:5: note: candidate: 'template<class _Tp, long unsigned int _Nm> constexpr _Tp* std::end(_Tp (&)[_Nm])'
  106 |     end(_Tp (&__arr)[_Nm]) noexcept
      |     ^~~
/usr/include/c++/14/bits/range_access.h:106:5: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:115:31: note: candidate: 'template<class _Tp> _Tp* std::end(valarray<_Tp>&)'
  115 |   template<typename _Tp> _Tp* end(valarray<_Tp>&) noexcept;
      |                               ^~~
/usr/include/c++/14/bits/range_access.h:115:31: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/range_access.h:116:37: note: candidate: 'template<class _Tp> const _Tp* std::end(const valarray<_Tp>&)'
  116 |   template<typename _Tp> const _Tp* end(const valarray<_Tp>&) noexcept;
      |                                     ^~~
/usr/include/c++/14/bits/range_access.h:116:37: note:   candidate expects 1 argument, 0 provided