foo.cc: In function 'int main()':
foo.cc:13:18: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   13 |         for(i=0;i<s.size();i++)
      |                 ~^~~~~~~~~
foo.cc:15:29: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   15 |                 if(s[i]>='A'&&s[i]<='Z'||s[i]>='a'&&s[i]<='z')
foo.cc:22:34: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |                         for(j=1;j<s1.size();j++)
      |                                 ~^~~~~~~~~~
foo.cc:30:18: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |         for(i=1;i<s1.size();i++)
      |                 ~^~~~~~~~~~

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