File handling oop

#include<iostream>
#include<fstream>

using namespace std;

class emp{
string empid;
string name;

public:
emp(){
    empid = '0';
    name = "abc";
}

void accept(){
    cout<< "Enter employee details" << endl;
    cout << "Enter employee id: " << endl;
    cin >> empid;
    cout << "Enter employee name: " << endl;
    cin >> name;
}

void display(){
    cout << "Employee ID: " << empid << endl;
    cout << "Employee name: " << name << endl;
}

string retid(){
    return empid;
}

string retname(){
    return name;
}

/*void search(int id){
        if(id == empid){
            display();
        }
        else{
            cout<<"Data not found"<<endl;
        }
}*/

};

int main(){
    emp e1[4], e2[4], e3[3], e4[4];
    fstream file, file2;
    string deleteid;
    string updateid;
    string searchid;
    int ch = 10;
    int flag = 0;
    while(ch != 0){
        cout << "Enter your choices: " << endl;
        cout << "1: Write in file" << endl;
        cout << "2: Read from file" << endl;
        cout << "3: Search in file" << endl;
        cout << "4: Delete data in file" << endl;
        cout << "5: Update data in file"<<endl;
        cout << "0: Exit" << endl;
        cin >> ch;
        switch(ch){
            case 1:
            file.open("/home/pccoe/Desktop/empdata.txt");
            for(int i = 0; i < 4; i++){
                e1[i].accept();
                file.write((char*)&e1[i], sizeof(e1[i]));
            }
            file.close();
            break;
            case 2:
            file.open("/home/pccoe/Desktop/empdata.txt");
            for(int i = 0; i < 4; i++){
                file.read((char*)&e2[i], sizeof(e2[i]));
                e2[i].display();
            }
            file.close();
            break;
            case 3:
            cout << "Enter the id to search: " << endl;
            cin >> searchid;
            file.open("/home/pccoe/Desktop/empdata.txt");
            for(int i = 0; i < 4; i++){
                file.read((char*)&e2[i], sizeof(e2[i]));
                if(e2[i].retid() == searchid){
                    cout << "Data found" << endl;
                    cout << e2[i].retname() << endl;
                    flag = 1;
                }
            }
            if(flag == 0){
                cout << "data not found" << endl;
            }
            file.close();
            break;
            case 4:
            cout << "Enter the id to delete: " << endl;
            cin >> deleteid;
            file2.open("/home/pccoe/Desktop/empdatanew.txt");
            for(int i = 0; i < 4; i++){
                    if(e1[i].retid() != deleteid){
                       file2.write((char*)&e1[i], sizeof(e1[i]));
                    }
            }
            file2.close();
            file2.open("/home/pccoe/Desktop/empdatanew.txt");
            for(int i=0;i<3;i++){
                file2.read((char*)&e3[i],sizeof(e3[i]));
                cout<<e3[i].retname()<<endl;
            }
            file2.close();
            //remove("/home/pccoe/Desktop/emp.txt");
            //rename("/home/pccoe/Desktop/empdatanew.txt", "/home/pccoe/Desktop/empdata.txt");
            break;
            case 5:
                int pos;
            cout << "Enter the id to update: " << endl;
            cin >> updateid;
            file.open("/home/pccoe/Desktop/empdata.txt");
            for(int i = 0; i < 4; i++)
            {
                 pos=file.tellg();

                file.read((char*)&e2[i], sizeof(e2[i]));
                     if(e2[i].retid() == updateid)
                     {
                        e2[i].accept();
                        flag=1;

                     }
                     file.close();
            }
            cout<<pos;
            if(flag == 1){
                 file.open("/home/pccoe/Desktop/empdata.txt");
                            for(int i = 0;i < 4; i++){
                                file.seekp(pos);
                                file.write((char*)&e2[i],sizeof(e2[i]));

                            }
                            file.close();
            }
            break;
        }
    }
    return 0;
}