foo.cc: In function ‘int main()’:
foo.cc:15:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   15 |         for(int i=0;i<a.size();i++) cout<<a[i]<<(i<a.size()-1?" ":"");
      |                     ~^~~~~~~~~
foo.cc:15:51: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   15 |         for(int i=0;i<a.size();i++) cout<<a[i]<<(i<a.size()-1?" ":"");
      |                                                  ~^~~~~~~~~~~