foo.cc: In function 'bool cmp(std::string, std::string)':
foo.cc:13:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |         for(int i=0;i<a.length();i++){
      |                     ~^~~~~~~~~~~
foo.cc:9:13: warning: variable 'm' set but not used [-Wunused-but-set-variable]
    9 |         int m=a.length();
      |             ^
foo.cc: In function 'int main()':
foo.cc:33:9: error: 'sort' was not declared in this scope; did you mean 'short'?
   33 |         sort(w,w+n);
      |         ^~~~
      |         short

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