foo.cc: In function 'int main()':
foo.cc:9:19: 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 < s.size(); i++)
      |                 ~~^~~~~~~~~~
foo.cc:11:13: warning: format '%f' expects argument of type 'double', but argument 2 has type 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wformat=]
   11 |  printf("%.2f", 100 / s.size() * sum);
      |          ~~~^   ~~~~~~~~~~~~~~~~~~~~
      |             |                  |
      |             double             std::__cxx11::basic_string<char>::size_type {aka long unsigned int}
      |          %.2ld

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