Language: C++

#include<iostream>
using namespace std;

int main(){
	char c;
  	cin >> c;
    string s = "aeiou";
    if(s.find()>=0){
      cout << "vowel\n";
    }else{
      cout << "consonant\n";
    }
}

Compiler output:
a.cc: In function 'int main()':
a.cc:8:14: error: no matching function for call to 'std::__cxx11::basic_string<char>::find()'
    8 |     if(s.find()>=0){
      |        ~~~~~~^~
In file included from /usr/include/c++/14/string:54,
                 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/bits/basic_string.h:2720:9: note: candidate: 'template<class _Tp> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::_If_sv<_Tp, typename __gnu_cxx::__alloc_traits<typename __gnu_cxx::__alloc_traits<_Alloc>::rebind<_CharT>::other>::size_type> std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::find(const _Tp&, size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>]'
 2720 |         find(const _Tp& __svt, size_type __pos = 0) const
      |         ^~~~
/usr/include/c++/14/bits/basic_string.h:2720:9: note:   candidate expects 1 argument, 0 provided
/usr/include/c++/14/bits/basic_string.h:2691:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::find(const _CharT*, size_type, size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]'
 2691 |       find(const _CharT* __s, size_type __pos, size_type __n) const
      |       ^~~~
/usr/include/c++/14/bits/basic_string.h:2691:7: note:   candidate expects 3 arguments, 0 provided
/usr/include/c++/14/bits/basic_string.h:2706:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::find(const std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]'
 2706 |       find(const basic_string& __str, size_type __pos = 0) const
      |       ^~~~
/usr/include/c++/14/bits/basic_string.h:2706:7: note:   candidate expects 2 arguments, 0 provided
/usr/include/c++/14/bits/basic_string.h:2740:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::find(const _CharT*, size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]'
 2740 |       find(const _CharT* __s, size_type __pos = 0) const _GLIBCXX_NOEXCEPT
      |       ^~~~
/usr/include/c++/14/bits/basic_string.h:2740:7: note:   candidate expects 2 arguments, 0 provided
/usr/include/c++/14/bits/basic_string.h:2758:7: note: candidate: 'std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::size_type std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::find(_CharT, size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int]'
 2758 |       find(_CharT __c, size_type __pos = 0) const _GLIBCXX_NOEXCEPT;
      |       ^~~~
/usr/include/c++/14/bits/basic_string.h:2758:7: note:   candidate expects 2 arguments, 0 provided