foo.cc: In function ‘int main()’:
foo.cc:7:18: 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();)
      |                 ~^~~~~~~~~
foo.cc:10:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   10 |         for(int j=i;j<i+s1.size() ;j++)
      |                     ~^~~~~~~~~~~~
foo.cc:16:26: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::__cxx11::basic_string<char>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   16 |             for(int k=0;k<s2.size();k++)cout<<s2[k];
      |                         ~^~~~~~~~~~