How to Use Read and Write Methods in C++

Program 1

// read write method (How to store object in file)
#include<iostream>
#include<fstream>
#define clrscr() system("cls")
using namespace std;
class Employee
{
    private :
    int empid;
    char name[20];
    char dname[20];
    int salary;
    public:
    void getdata()
    {
        cout<<"\nEnter a id: ";
        cin>>empid;
        cout<<"\n Enter Name: ";
        cin>>name;
        cout<<"\n Enter Department Name: ";
        cin>>dname;
        cout<<"\n Enter Salary: ";
       cin>>salary;
    }
    void showdata()
    {
        cout<<"\n Emp Id:"<<empid;
        cout<<" Emp Name: "<<name;
        cout<<" Department Name: "<<dname;
        cout<<" Salary: "<<salary;
        cout<<"\n";
    }
};
class Emp_File
{
    private:
    Employee buffer;
    public:
    void diskin();
    void diskout();
};
void Emp_File::diskin()
{
    fstream fout("g://cppdata/empinfo.txt",ios::app);
    if(fout.is_open())
    {
        char ch;
     do
     {
        buffer.getdata();  // data read
        fout.write((char*)&buffer, sizeof(buffer));  // Write object
        cout<<"\n Want to continue";
        cin>>ch;
     }while(ch=='y' || ch=='Y');

        fout.close(); //close file
    }
    else
    cout<<"File error";
}


void Emp_File::diskout()
{
    fstream fin("g://cppdata/empinfo.txt",ios::in);  // open file in read mode
    if(fin.is_open())
     {
        fin.read((char*) & buffer,sizeof(buffer)); 
        while(fin)       
        { 
          buffer.showdata();  //display data 
          fin.read((char*) & buffer,sizeof(buffer));  // read object
       }

        fin.close(); // close
    }
    else
    cout<<"File error";
}


int main()
{
    int choice;
    Emp_File ef;
    clrscr();
    do
    {
    cout<<"\n-----------------File Menu---------------";
    cout<<"\n 1. Write Data \n 2 Read Data\n 3.Exit";
    cout<<"\n-----------------------------------------";
    cout<<"\nEnter your choice";
    cin>>choice;
    switch(choice)
    {
          case 1:ef.diskin();break;
          case 2: ef.diskout();break;
          case 3: break;
          default:cout<<"\n Invalid chioce";

    }
    }while(choice!=3);

    return 0;
}