Language: C++

#include<iostream>
#include<cmath>
using namespace std;

int f(int n){
  if(n==-1){
    return 0;
  }else{
    int output=0;
    output+=(n+1)%2;
    for(int i=1;i<40;i++){
      int digit=pow(2,i);
      int mod=(n+1)%(2*digit);
      int k;
      if(mod<=digit){
        k=0;
      }else{
        k=mod%2;
      }
      output+=digit*k;
    }
    return output;
  }
}
    
int main(){
  int a,b;
  cin>>a>>b;
  cout<<f(a-1)^f(b);
  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:29:15: error: no match for 'operator^' (operand types are 'std::basic_ostream<char>' and 'int')
   29 |   cout<<f(a-1)^f(b);
      |   ~~~~~~~~~~~~^~~~~
      |       |         |
      |       |         int
      |       std::basic_ostream<char>
a.cc:29:15: note: candidate: 'operator^(int, int)' (built-in)
   29 |   cout<<f(a-1)^f(b);
      |   ~~~~~~~~~~~~^~~~~
a.cc:29:15: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'int'
In file included from /usr/include/c++/14/bits/memory_resource.h:38,
                 from /usr/include/c++/14/string:68,
                 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/cstddef:146:3: note: candidate: 'constexpr std::byte std::operator^(byte, byte)'
  146 |   operator^(byte __l, byte __r) noexcept
      |   ^~~~~~~~
/usr/include/c++/14/cstddef:146:18: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::byte'
  146 |   operator^(byte __l, byte __r) noexcept
      |             ~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:94:3: note: candidate: 'constexpr std::_Ios_Fmtflags std::operator^(_Ios_Fmtflags, _Ios_Fmtflags)'
   94 |   operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:94:27: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::_Ios_Fmtflags'
   94 |   operator^(_Ios_Fmtflags __a, _Ios_Fmtflags __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:144:3: note: candidate: 'constexpr std::_Ios_Openmode std::operator^(_Ios_Openmode, _Ios_Openmode)'
  144 |   operator^(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:144:27: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::_Ios_Openmode'
  144 |   operator^(_Ios_Openmode __a, _Ios_Openmode __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/ios_base.h:191:3: note: candidate: 'constexpr std::_Ios_Iostate std::operator^(_Ios_Iostate, _Ios_Iostate)'
  191 |   operator^(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
      |   ^~~~~~~~
/usr/include/c++/14/bits/ios_base.h:191:26: note:   no known conversion for argument 1 from 'std::basic_ostream<char>' to 'std::_Ios_Iostate'
  191 |   operator^(_Ios_Iostate __a, _Ios_Iostate __b) _GLIBCXX_NOTHROW
      |             ~~~~~~~~~~~~~^~~