/in/foo.cc: In function 'int main()':
/in/foo.cc:7:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    7 |         for(int i=0;i<s.size();i++)
      |                     ~^~~~~~~~~
/in/foo.cc:10:29: warning: value computed is not used [-Wunused-value]
   10 |                         s[i]=='6';
/in/foo.cc:12:29: warning: value computed is not used [-Wunused-value]
   12 |                         s[i]=='9';
/in/foo.cc:17:30: warning: overflow in conversion from 'int' to '__gnu_cxx::__alloc_traits<std::allocator<char>, char>::value_type' {aka 'char'} changes value from '1000000' to '64' [-Woverflow]
   17 |                         s[i]=1000000;
      |                              ^~~~~~~