c_cpp read_write_data_as_raw.cpp

Posted 2021-05-14

#include <iostream>
#include <fstream>
using namespace std;

struct Data {
  int number;
  double buy;
  double sale;
  int amount;
};

int main(void) {
  int number = 1;
  int padding = -1;
  double buy = 3.4;
  double sale = 5.2;
  int amount = 30;

  ofstream out("data.out");
  out.write(reinterpret_cast<char*>(&number), sizeof(int));
  out.write(reinterpret_cast<char*>(&padding), sizeof(int)); // There is padding here
  out.write(reinterpret_cast<char*>(&buy), sizeof(double));
  out.write(reinterpret_cast<char*>(&sale), sizeof(double));
  out.write(reinterpret_cast<char*>(&amount), sizeof(int));
  out.close();

  ifstream in("data.out");
  Data receiver;

  while (true) {
    in.read(reinterpret_cast<char*>(&receiver), sizeof(Data));
    cout << "{"
         << receiver.number << ", "
         << receiver.buy << ", "
         << receiver.sale << ", "
         << receiver.amount
         << "}" << endl;
    if (in.eof()) break;
  }

}