foo.cc: In function 'int main()':
foo.cc:11:22: 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.length();i++)
      |                     ~^~~~~~~~~~~
foo.cc:14:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |                 if(idx<s.length())
      |                    ~~~^~~~~~~~~~~
foo.cc:9:19: warning: unused variable 'cnt' [-Wunused-variable]
    9 |         int idx=0,cnt=0;
      |                   ^~~

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