# CPP Logical questions Solution

Part A

·         Locate the errors in the following code. You will notice, not every line will contain a mistake. Pay close attention to the line preceding it. Look out for uninitialized pointers, NULL pointers, pointers to deleted objects, and confusing pointers with objects.

1 int* p = new int;

2 p = 5;

3 *p = *p + 5;

4 Employee e1 = new Employee(Hacker, Harry, 34000);

5 Employee e2;

6 e2->set_salary(38000);

7 delete e2;

8 Time* pnow = new time ();

9 Time* t1 = new Time(2,   0,   0);

10 cout <<  t1->seconds_from(pnow);

11 delete*t1;

12 cout << t1->get_seconds();

13 Employee* e3 = new Employee(Lin, Lisa, 68000);

14 cout << e3.get_salary();

15 Time* t2 = new Time(1, 25, 0);

16 cout << *t2.get_minutes();

17 delete t2;

Part B

·         Implement a class person with the following fields:

The name

A pointer to the persons best friend

A popularity counter that indicates how many people have this person as their best friend

·         Write a program that reads in a list of names, allocates a new Peron for every one of them, and places them in a vector<Person*>. Next, request the name of each best friend for every Person objects. Find the object matching the friends name, and call a set_best_friend member function to update the pointer and counter. Lastly, print out every Person objects. Labeling the name, best friend, and popularity counter for all.

#include <iostream>

#include <string>

#include <vector>

#include <iomanip>

using namespace std;

class Person

{

public :

Person(string name = “N/A” , int popularity = 0, Person* bfriend = NULL);

string getName();

void setName(string name);

int getPopularity();

void setPopularity(int pop);

string getBestFriend();

void setBestFriend(Person* bfriend);

private :

string name;  //The name

Person* bestfriend;  //A pointer to the persons best friend

int popularity;      //A popularity counter that indicates how many people have this person as their best friend

};

Person::Person(string fname, int fpopularity, Person* bfriend)

{

name = fname;

popularity = fpopularity;

bestfriend = bfriend;

}

string Person::getName()

{

return name;

}

void Person::setName(string fname)

{

name = fname;

}

int Person::getPopularity()

{

return popularity;

}

void Person::setPopularity(int pop)

{

popularity = pop;

}

string Person::getBestFriend()

{

return bestfriend->getName();

}

void Person::setBestFriend(Person* bfriend)

{

bestfriend = bfriend;

}

/*    Write a program that reads in a list of names, allocates a new Peron for every one of them,

and places them in a vector<Person*>. Next, request the name of each best friend for every

Person objects. Find the object matching the friends name, and call a set_best_friend member

function to update the pointer and counter. Lastly, print out every Person objects.

Labeling the name, best friend, and popularity counter for all.*/

Part C

·         Consider the following classes B and D:

Class B

{

Public;

B();

B( int n);

};

B::B()

{

cout << B::B()n;

}

B::B(int n)

cout <<  B::B( << n << )n;

}

Class D : Public B

{

public:

D();

D( int n);

private:

B b;

};

D::D()

{

cout << D::D()n;

}

D::D(int n) : B(n)

{

b = B(-n);

cout << D::D(<< n <<)n;

}

What does the following program print?

int main()

{

D d(3);

return 0;

}

·         Determine the answer by hand, not by compiling and running the program.

OUTPUT:

Part D

·         Implement a base class person. Derive classes Student and Professor from Person. Every Person has will have a name, and birthdate. Every student will have a major, and every professor will have an income. Write the class definitions, the constructors, and the member functions print() for all classes.