foo.cc: In function ‘int main()’:
foo.cc:8:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
    8 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
foo.cc:12:28: error: ‘x’ was not declared in this scope
   12 |                         if(x==1&&t.size()<=12&&t.size()>=6)
      |                            ^