/in/foo.cc: In function 'int main()':
/in/foo.cc:9:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |         for(int i=0;i<a.length();i++)
      |                     ~^~~~~~~~~~~
/in/foo.cc:16:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |         for(int i=0;i<a.length();i++)
      |                     ~^~~~~~~~~~~
/in/foo.cc:20:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |                         for(int j=i;j<a.length()-1;j++)
      |                                     ~^~~~~~~~~~~~~
/in/foo.cc:26:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |         for(int i=0;i<a.length()-1;i++)
      |                     ~^~~~~~~~~~~~~