OpenFile

FILE* open (char* filename);
int write(FILE* fd, char* str);
int close(FILE* fd);

class File {
  FILE* fd;
public:
  File(string filename) {
    fd = open(filename.to_c_str());
  }
  
  void write(string line) {
    int result = write(fd, line.to_c_str());
    if (result) {
      throw exception; 
    }
  }
  
  ~File() {
    close(fd);
  }
}


void main() {
  File f("file.txt");
  f.write("test");
  
  // what will happen?
  appendLine(f, "line1");
  appendLine(f, "line2");
}

void appendLine(File f, string line) {
  f.write(line);
}