{
vector<int> vec = {1, 2, 3, 4, 5, 6};
for (auto s:vec) cout<<s<<" "; cout<<endl;

int i=0;
for (i=0; i<vec.size(); i++) {
  cout<<vec[i]<<" ";
  if(vec[i] == 4) break;
}
cout<<endl;

vec.erase(vec.begin(), vec.begin() + i+1); // {4, 5, 6}

for (auto s:vec) cout<<s<<" "; cout<<endl;

}

=================================================
Processing vector_erase.C...
1 2 3 4 5 6
1 2 3 4
5 6