c++中使用fstream读取对象

Reading object using fstream in C++

本文关键字：读取 取对象 fstream c++      更新时间：2023-10-16

我试图使用fstream将对象写入文件并读取后，但当我尝试使用cout显示屏幕上读取的对象时，出现了错误消息Segmentation fault: 11。有人能帮我破解这个密码吗?提前感谢!

Produto *p1 = new Produto(1, "Refrigerante");
cout << "Produto p1 (pre serializacao): (" << p1->codigo << ") " << p1->descricao << endl;
ofstream serializationWriter;
serializationWriter.open("myobject.dat", ios::binary);
serializationWriter.write((char *)&p1, sizeof(p1));
Produto *p2;
ifstream serializationReader;
serializationReader.open("myobject.dat", ios::binary);
serializationReader.read((char *)&p2, sizeof(p2));
cout << "Produto p2 (pos serializacao): (" << p2->codigo << ") " << p2->descricao << endl;

您需要为类producto提供一些序列化机制。例如:

class Produto {
  // ...
private: 
  std::string m_str;
private: 
  friend ostream& operator<<(ostream& stream, const Produto& obj);
  friend istream& operator>>(istream& stream, Prodoto& obj)
};
ostream& operator<<(ostream& stream, const Produto& obj)
{
  // Write all data to stream.
  // ...
  stream << obj.m_str;
  return stream;
}
istream& operator>>(istream& stream, Prodoto& obj)
{
  // Read all data from strem.
  // ...
  stream >> obj.m_str;
  return stream; 
}

然后按如下方式使用:

Produto p1(1, "Refrigerante");
ofstream serializationWriter;
// ...
serializationWriter << p1;
Produto p2;
ifstream serializationReader;
// ...
serializationReader >> p2;

详细信息请参见重载ostream istream operator

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