How do I save an object containing a vector of another object into file and read back from file using binary files in C++?

This is my code for reading and Writing vectors; I get no errors while execution, but whenever I read back from it; it gives random values of integer instead of 50, and 100. What is it that I am doing wrong?

I have used vector objects inside of another object, and I am trying to file it using binary filing of objects.

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

class Rest{
    int value;
    public:
        void setvalue(int value){this->value=value;}
        int getvalue(){return value;}
};

class Admin{
    vector<Rest> restaurant;
    public:
        Admin(){}

        void setValue(int value){
            Rest obj1;
            Rest obj2;
            obj1.setvalue(value);
            obj2.setvalue(value+50);
            restaurant.push_back(obj1);
            restaurant.push_back(obj2);
        }
        vector<Rest> getRestFromFile(){
            Admin obj;
            fstream getsavedvector("Testsave.BIN", ios::in | ios::binary);
            getsavedvector.read(reinterpret_cast<char*> (&obj), sizeof(obj));
            getsavedvector.close();

            return obj.getRest();
        }
        void setRestVectorToFile(Admin obj){
            fstream savevector("Testsave.BIN", ios::out | ios::binary);
            savevector.write(reinterpret_cast<char*> (&obj),sizeof(obj));
            savevector.close();
        }
        void setRestVector(vector<Rest> restaurant){
            for(int i=0;i<restaurant.size();i++){
                this->restaurant.push_back(restaurant[i]);
            }
        }
        vector<Rest> getRest(){
            return this->restaurant;
        }
        void Display(){
            for(auto v: restaurant){
                cout<<v.getvalue()<<endl;
            }

        }
};

int main()
{    
    Admin obj;
    obj.setValue(50);
    obj.setRestVectorToFile(obj);

    Admin obj2;
    obj2.setRestVector(obj2.getRestFromFile());
    obj2.Display();
}