std::ifstream inFile("file");
  std::count(std::istreambuf_iterator<char>(inFile),
             std::istreambuf_iterator<char>(), 'n');

int numLines = 0;
ifstream in("file.txt");
std::string unused;
while ( std::getline(in, unused) )
   ++numLines;

int numLines = 0;
ifstream in("file.txt");
//while ( ! in.eof() )
while ( in.good() )
{
   std::string line;
   std::getline(in, line);
   ++numLines;
}