/in/foo.cc: In function 'int main()':
/in/foo.cc:20:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |                 if(i<s1.size()) t+=s1[i]-'0';
      |                    ~^~~~~~~~~~
/in/foo.cc:21:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |                 if(i<s2.size()) t+=s2[i]-'0';
      |                    ~^~~~~~~~~~
/in/foo.cc:32:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   32 |         for(int i=0;i<a.size();i++) cout<<a[i];
      |                     ~^~~~~~~~~