3.4

4.

 #include <iostream>

using namespace std;

class Student

{

public:

Student(int n,int s):num(n),score(s){}

void display();

private:

int num;

int score;

};

void Student::display()

{

 cout<<num<<" "<<score<<endl;

}

int main()

{

Student stud[5]={Student(1,98),Student(2,97),Student(3,96),Student(4,95),Student(5,94)};

Student *p=stud;

for(i=0;i<3;p=+2,i++)

p->display();

 return 0;

}