foo.cc: In function ‘void GetPrimes(int, int)’:
foo.cc:12:30: warning: comparison of integer expressions of different signedness: ‘int’ and ‘std::vector<int>::size_type’ {aka ‘long unsigned int’} [-Wsign-compare]
   12 |                 for(int j=0;j<Primes.size()&&i*Primes[j]<=n;j++)
      |                             ~^~~~~~~~~~~~~~
foo.cc: In function ‘int main()’:
foo.cc:25:21: warning: unused variable ‘ans’ [-Wunused-variable]
   25 |                 int ans=0;
      |                     ^~~