foo.cc: In function 'int main()':
foo.cc:11:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   11 |  {for(int i=0;i<s.size();i++)
      |               ~^~~~~~~~~
foo.cc:32:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 | for(int i=0;i<s.size();i++)
      |             ~^~~~~~~~~
foo.cc:35:3: warning: suggest explicit braces to avoid ambiguous 'else' [-Wdangling-else]
   35 | if(s[i]=='0')
      |   ^

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