foo.cc: In function ‘bool bin(std::string)’:
foo.cc:7:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
    7 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
foo.cc: In function ‘bool oct(std::string)’:
foo.cc:14:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   14 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
foo.cc: In function ‘bool dec(std::string)’:
foo.cc:21:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   21 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
foo.cc: In function ‘bool hex(std::string)’:
foo.cc:28:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   28 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~