Create binray file in constructor - c++

Question

I write a small Store that contain Item. I create two function one to print content of file one to sort the records and insert them back into file. With the initializer list it display correctly the content of file, but said that there is "Error with file". How to correct this issue and what is the best way to create a binary file in constructor
#pragma once
#include <iostream>
#include <fstream>
#include <cstring>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;
struct Item
{
char name[20];
int code;
float price;
int quantity;
Item() { code = 0, price = 0, quantity = 0;
char name1[20] = { 0 }; strcpy_s(name, 20, name1);
}
Item(const char* name, int code, float price, int quantity)
{
strcpy_s(this->name, strlen(name) + 1, name);
this->code = code;
this->price = price;
this->quantity = quantity;
}
friend ostream& operator<<(ostream& os, Item& item)
{
os << "Name: " << item.name << endl;
os << "code: " << item.code << endl;
os << "price: " << item.price << endl;
os << "quantity: " << item.quantity << endl << endl;
return os;
}
bool operator!()
{
return code != 0;
}
};
class Store
{
private:
int size = 100;
fstream file;
string fileName;
public:
Store(string fname);
~Store();
Store& operator+=(Item& myItem);
friend ostream& operator<<(ostream&, Store&);
void sortStore();
};
#include "Store.h"
Store::Store(string fname) : file(fname,ios::binary)
{
Item tmp;
if (!file)
cout << "Error with file" << endl;
for (int i = 0; i < size; i++)
file.write((char*)&tmp, sizeof(Item));
//file.close();
file.open(fname, ios::binary | ios::in | ios::out);
}
Store::~Store()
{
file.close();
}
Store& Store::operator+=(Item& myItem)
{
file.write((char*)&myItem, sizeof(myItem));
return (*this);
}
ostream& operator<<(ostream& out, Store& store)
{
Item tmp;
store.file.seekg(0, ios::beg);
for (int i = 0; i < store.size; i++)
{
store.file.read((char*)&tmp, sizeof(Item));
if (!tmp)
cout << i << ": " << tmp;
}
return out;
}
void Store::sortStore()
{
Item tmp;
vector<Item> items;
file.seekg(0, ios::beg);
while (!file.eof())
{
file.read((char*)&tmp, sizeof(Item));
items.push_back(tmp);
}
sort(items.begin(), items.end(), [](Item& first, Item& second)
{
return first.code < second.code;
});
file.clear();
remove("store.dat");
Store("store.dat");
file.seekp(0, ios::beg);
for (auto it = items.begin(); it < items.end(); it++)
file.write((char*)&(*it), sizeof(Item));
}
int main()
{
Store ourStore("store.dat");
Item apple("apple", 45, 12.2, 10);
Item ananas("ananas", 12, 27, 10);
Item strawberry("strawberry", 1, 24.2, 5);
Item banana("banana",23,14.2, 12);
ourStore.operator+=(apple);
ourStore.operator+=(ananas);
ourStore.operator+=(strawberry);
ourStore.operator+=(banana);
int choice = -1;
while (choice != 0)
{
cout << "1.Sorting, 2 Print" << endl;
switch (choice)
{
case 1:
cout << "Sorting" << endl;
ourStore.sortStore();
case 2:
cout << "Print" << endl;
cout << ourStore << endl;
}
cin >> choice;
}
return 0;
}

Answer 1

The local variable file in Store::Store hides the member variable Store::file.
You want an initializer list:
Store::Store : file(fname, ios::binary)
{
// ...