Не могу разобраться. public/private/protected

#include <iostream>
 
#include <string>
 
#include <time.h>
 
using namespace std;
 
struct student
 
{
 
string Name;
 
string Sur_Name;
 
string Adress;
 
double Rating;
 
string e_adress;
 
};
 
int main ()
 
{
 
student bi2_1[5];
 
bi2_1[0].Name="Sergey";
 
bi2_1[0].Sur_Name="Sergey";
 
bi2_1[0].Adress="Moscow";
 
bi2_1[0].Rating=3.7;
 
bi2_1[0].e_adress="s.sergey@mail.ru";
 
bi2_1[1].Name="Dasha";
 
bi2_1[1].Sur_Name="Dasha";
 
bi2_1[1].Adress="Moscow";
 
bi2_1[1].Rating=1.8;
 
bi2_1[1].e_adress="dasha@mail.ru";
 
bi2_1[2].Name="Sasha";
 
bi2_1[2].Sur_Name="Sasha";
 
bi2_1[2].Adress="Moscow";
 
bi2_1[2].Rating=2.5;
 
bi2_1[2].e_adress="Sasha@mail.ru";
 
bi2_1[3].Name="Andrey";
 
bi2_1[3].Sur_Name="Andrey";
 
bi2_1[3].Adress="Moscow";
 
bi2_1[3].Rating=2.0;
 
bi2_1[3].e_adress="a.andrey@mail.ru";
 
bi2_1[4].Name="Nastya";
 
bi2_1[4].Sur_Name="Nastya";
 
bi2_1[4].Adress="Moscow";
 
bi2_1[4].Rating=3.1;
 
bi2_1[4].e_adress="asya_asya@mail.ru";
 
string Name;
 
cout <<"\n\n Write a name:";
 
cin >>Name;
 
for (int i=0; i<5; i++)
 
{
 
if (bi2_1[i].Name==Name)
 
{
 
cout <<"Name "<<bi2_1[i].Name<<endl<<"Sur_Name" <<bi2_1[i].Sur_Name<<endl<<"Rating "<<bi2_1[i].Rating<<endl<<"e_adress" <<bi2_1[i].e_adress<<endl;
 
cout <<endl;
 
}
 
}
 
time_t seconds=time(NULL);
 
tm*timeinfo=localtime(&seconds);
 
cout <<"Time of searching: " <<asctime(timeinfo)<<endl;
 
return(0);
 
}

struct Student
{
public:
    
private:
 
protected:
 
};

public string Name;
 
public string Sur_Name;
 
private string Adress;
 
public double Rating;
 
public/private string e_adress;

bi2_1[0].Rating=3.7;