如何在读取文件时修复 C++ 上的分段错误（核心转储）错误？

当我尝试在 c++ 17 上运行此代码时，它可以工作，但在 c++ 上却没有。第一次运行时，它只给我最后输入元素的字符串值，但是当我第二次运行它时，它显示分段错误（核心转储）错误。有人可以帮我弄这个吗？

这是我的代码：

#include<iostream>
#include<string>
#include<fstream>
#include<vector>
#include<iomanip>
#include <stdlib.h>
using namespace std;
void show1(string name,string type,string price,string quantity){
  cout<<"=======================================\n";
  cout<<setw(5)<<name<<setw(15)<<type<<setw(10)<<price<<setw(15)<<quantity<<"\n";
  cout<<"========================================\n";
}
template<class T>
void Readfile(T &obj,string fname,string name,string type,string price,string quantity){
  int i=1;
  ifstream f;
  f.open(fname,ios::in);
  f.seekg(0);
  Display(name,type,price,quantity);
  while(!f.eof()){
    f.read((char*)&obj, sizeof(obj));
    
    if(!f.eof())      {
      if(f.tellg()<0)
        {   i=0; break;}
          obj.putdata();
     }
    }
        
  f.close();
}

class Items{
    string name;
    double price;
    int quantity;
    public:
    string itemObj;
        
    void getdata(string obj){
        cout<<"Enter name, price and quantity: \n";
        cin>>name>>price>>quantity;
        itemObj=obj;
    }
    void putdata(){
      cout<<setw(5)<<name<<setw(10)<<itemObj<<setw(12)<<price<<setw(10)<<quantity<<"\n";
    }
    
    void writeToFile(int n,string obj);
    void ReadFile_item();
    int check(string temp_name);
    void refill_Item(int qty);
    double checkout_price(int qty);

    
}item;

class CD:public Items{
 public:
  void Add_CD();
  
}cd;




double Items::checkout_price(int qty){
  if(quantity>=qty){
    quantity-=qty;
    cout<<"File Updated";
    return price*qty;
  }
  else{
    cout<<"\nNot enough stock";
    return 0;
  }
}  
void Items::writeToFile(int n,string obj){
    ofstream f;
    f.open("stock.txt",ios::out|ios::app);
       
    for(int i=0;i<n;i++){
      item.getdata(obj);
      f.write((char*)&item, sizeof(item));
      cout<<"File Updated\n";
    }
    f.close();
       
}

void Items:: ReadFile_item(){
   Readfile(item,"stock.txt","Name","Item type"," Price ","Available stock");
}



void Add_item_obj(string obj){
  int n;
  cout<<"Enter no. of "<<obj<<"'s to add: \n";
  cin>>n;
  item.writeToFile(n,obj);
}
void CD::Add_CD(){
  Add_item_obj("CD");
}



void main_menu(){
  int i=0;
  do{
    cout<<"============================\n";
    cout<<"-------MAIN MENU------------\n";
    cout<<"============================\n";
    cout<<"1. Sell Items\n";
    cout<<"2. Add Items\n";
    cout<<"4. View stock file\n";
    cout<<"5. Exit \n";
    
    cout<<"Enter your choice: ";
    cin>>i;

    switch(i){
      case 1: sell_items();
              break;
      
      case 2: writetoFile(1,"CD");
              break;

      case 3: item.ReadFile_item();
              break;

      

      default: cout<<"Exiting... \n";
                exit(0);
    }
  }while(i!=0);
}

int main(){
   main_menu();
    
    return 0;
}