Language: C++

#include <iostream>
#include <string>
#include <stdio.h>
#include <cmath>
#include <algorithm>
#include <stack>
#include <vector>
#include <queue>

using namespace std;
int main(void){
    string s;
    cin>>s;
    int a=s.size();
    for(int i=0;i<s;i++){
        cout<<x;
    }
    cout<<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:15:18: error: no match for 'operator<' (operand types are 'int' and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   15 |     for(int i=0;i<s;i++){
      |                 ~^~
      |                 | |
      |                 | std::string {aka std::__cxx11::basic_string<char>}
      |                 int
In file included from /usr/include/c++/14/string:48,
                 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/stl_iterator.h:448:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  448 |     operator<(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:448:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
/usr/include/c++/14/bits/stl_iterator.h:493:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator<(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  493 |     operator<(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:493:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::reverse_iterator<_Iterator>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
/usr/include/c++/14/bits/stl_iterator.h:1694:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator<(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1694 |     operator<(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1694:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
/usr/include/c++/14/bits/stl_iterator.h:1760:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1760 |     operator<(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1760:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::move_iterator<_IteratorL>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/string:51:
/usr/include/c++/14/bits/stl_pair.h:1045:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator<(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1045 |     operator<(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1045:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::pair<_T1, _T2>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:673:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator<(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  673 |     operator< (basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:673:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
/usr/include/c++/14/string_view:680:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator<(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  680 |     operator< (basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:680:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
/usr/include/c++/14/string_view:688:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator<(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  688 |     operator< (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:688:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   15 |     for(int i=0;i<s;i++){
      |                   ^
/usr/include/c++/14/bits/basic_string.h:3874:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3874 |     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3874:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
/usr/include/c++/14/bits/basic_string.h:3888:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 3888 |     operator<(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3888:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
/usr/include/c++/14/bits/basic_string.h:3901:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator<(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3901 |     operator<(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3901:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const _CharT*' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/tuple:2600:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator<(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2600 |     operator<(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2600:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::tuple<_UTypes ...>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
In file included from /usr/include/c++/14/deque:66,
                 from /usr/include/c++/14/stack:62,
                 from a.cc:6:
/usr/include/c++/14/bits/stl_deque.h:2334:5: note: candidate: 'template<class _Tp, class _Alloc> bool std::operator<(const deque<_Tp, _Alloc>&, const deque<_Tp, _Alloc>&)'
 2334 |     operator<(const deque<_Tp, _Alloc>& __x, const deque<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_deque.h:2334:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::deque<_Tp, _Alloc>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
In file included from /usr/include/c++/14/stack:63:
/usr/include/c++/14/bits/stl_stack.h:373:5: note: candidate: 'template<class _Tp, class _Seq> bool std::operator<(const stack<_Tp, _Seq>&, const stack<_Tp, _Seq>&)'
  373 |     operator<(const stack<_Tp, _Seq>& __x, const stack<_Tp, _Seq>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_stack.h:373:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::stack<_Tp, _Seq>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
In file included from /usr/include/c++/14/vector:66,
                 from a.cc:7:
/usr/include/c++/14/bits/stl_vector.h:2089:5: note: candidate: 'template<class _Tp, class _Alloc> bool std::operator<(const vector<_Tp, _Alloc>&, const vector<_Tp, _Alloc>&)'
 2089 |     operator<(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_vector.h:2089:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::vector<_Tp, _Alloc>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
In file included from /usr/include/c++/14/queue:66,
                 from a.cc:8:
/usr/include/c++/14/bits/stl_queue.h:397:5: note: candidate: 'template<class _Tp, class _Seq> bool std::operator<(const queue<_Tp, _Seq>&, const queue<_Tp, _Seq>&)'
  397 |     operator<(const queue<_Tp, _Seq>& __x, const queue<_Tp, _Seq>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_queue.h:397:5: note:   template argument deduction/substitution failed:
a.cc:15:19: note:   mismatched types 'const std::queue<_Tp, _Seq>' and 'int'
   15 |     for(int i=0;i<s;i++){
      |                   ^
In file included from /usr/include/c++/14/bits/ios_base.h:46:
/usr/include/c++/14/system_error:324:3: note: candidate: 'bool std::operator<(const error_code&, const error_code&)'
  324 |   o