#include <fstream>
#include <iostream>
#include <string>

class CharacterReader {
public:
  virtual char NextCharacter() = 0;
  virtual void Close() = 0;
};

class FastCharacterReaderImpl final : public CharacterReader {

public:
  FastCharacterReaderImpl();
  ~FastCharacterReaderImpl();

  char NextCharacter() override;
  void Close() override;

  unsigned int FileLength();

private:
  std::ifstream is_;
  unsigned int file_length_;
};

FastCharacterReaderImpl::FastCharacterReaderImpl() {
  is_.open("testtext2.txt");
  if (is_) {
    is_.seekg (0, is_.end);
    file_length_ = is_.tellg();
    is_.seekg (0, is_.beg);
  }
}

FastCharacterReaderImpl::~FastCharacterReaderImpl() {
  if (is_)
    is_.close();
}

unsigned int FastCharacterReaderImpl::FileLength() {
  return file_length_;
}

char FastCharacterReaderImpl::NextCharacter() {
    char c;
    if (!is_.eof())
      is_.get(c);
    return c;
}

void FastCharacterReaderImpl::Close() {
    is_.close();
}

int main ()
{
  FastCharacterReaderImpl obj;

  for (auto i = 0; i < obj.FileLength(); i++)
    std::cout << obj.NextCharacter();

  obj.Close();

  return 0;
}