Bekerja dengan teks file

#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <fstream>

using namespace std;

char nama_file[20];

void baca_file() {
  string line;
  char hasil[255];
  ifstream myfile (nama_file);
  if (myfile.is_open())
  {
    while ( getline (myfile,line) ) // dibaca 1 baris, lalu dimasukan variabel line
    {
      strcpy(hasil,line.c_str()); // hasil variabel line, diubah ke string dan dimasukkan ke hasil
      printf("hasil: %s \n",hasil);
    }
    myfile.close();
  }

  else cout << "Unable to open file"; 


}


void tulis_file() {
  ofstream myfile (nama_file);
  if (myfile.is_open())
  {
    myfile << "This is a line.\n";
    myfile << "This is another line.\n";
    myfile.close();
  }
  else cout << "Unable to open file";

}

int main() {
  system("cls"); // membersihkan layar



  printf("Nama file  : ");gets(nama_file);
  tulis_file();
  baca_file(); 

  getch();
  return 0;
}

Nama Customer = Stephen (inputan)
Tipe Kamar  = Vip atau Presiden atau Ekonomi (pilih salah satu)
Harga Kamar = (inputan)
Lama Inap =  (inputan)
SubTotal1 =  (harga kamar * lama inap)
Total Pesanan Kamar = 7 (inputan)
Biaya Tambahan = 125000 (inputan)
SubTotal2 =  (SubTotal1 * total pesanan kamar + biaya tambahan)
Pajak  = 12.5% * SubTotal 2
========================================================== 
Total Bayar Customer  = (SubTotal 2 + Pajak)