foo.cc: In function 'int main()':
foo.cc:12:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |  for(int i=0;i<str.size()-1;i++)
      |              ~^~~~~~~~~~~~~
foo.cc:20:15: 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 i=0;i<str.size();i++)
      |              ~^~~~~~~~~~~
foo.cc:11:6: warning: unused variable 'j' [-Wunused-variable]
   11 |  int j=0;
      |      ^

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