foo.cc: In function 'int main()':
foo.cc:17:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |   for(int j=0;j<prime.size()&&i*prime[j]<n;j++)
      |               ~^~~~~~~~~~~~~
foo.cc:25:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |  for(int i=0;i<prime.size();i++)
      |              ~^~~~~~~~~~~~~

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