foo.cc: In function ‘int main()’:
foo.cc:37:22: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   37 |         for(int j=0;j<prime.size()&&i*prime[j]<=100000;j++)
      |                     ~^~~~~~~~~~~~~
foo.cc:55:18: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   55 |     for(int i=0;i<prime.size()&&prime[i]<=x;i++)
      |                 ~^~~~~~~~~~~~~