Self-test 1:
C++ Class Basics

If a member of a class is ____, you cannot access it outside the class.
1. static
2. public
3. private
4. constant
Solution

private
In C++, class is a reserved word, and it defines only a(n) ____; no memory is allocated.

Solution

data type
If a class object is passed by _____, the contents of the member variables of the actual parameter are copied into the corresponding member variables of the formal parameter.
1. value
2. reference
3. either value or reference
4. None of the above
Solution

value
The word ____ at the end of a member function heading specifies that the function cannot modify the member variables of that object.
1. protected
2. private
3. public
4. const
Solution

const
If a member function is used only to implement other member functions of a class and the user does not need to access the function, you should declare it ____

Solution

private
Which of the following is true regarding parameter passing with class objects?
1. A class object may be passed by reference only.
2. A class object may be passed by value only.
3. A class object may be passed by reference or by value.
4. A class object may not be passed as a parameter.
Solution

A class object may be passed by reference or by value.
A constructor:
1. Obtains memory for a new variable
2. Enables the initialization of an object as it is created
3. Constructs a new data type
4. None of the above
Solution

Enables the initialization of an object as it is created
The members of a class, by default, are:
1. public
2. protected
3. private
4. mandatory to specify
Solution

private

What is the output of the following code

#include <iostream>
using namespace std;

inline int cubic(int s)
{
    return s*s*s;
}

int main()
{
    cout << "The cubic of 3 is: " << cubic(3) << "\n";
    return 0;
}

Solution

The cubic of 3 is: 27

What is the output of the following program when 45 and 15 are entered (in the order)?

#include <iostream>
using namespace std;

class Operation
{
    int a, b, aa, ss, mm, vv;
  public:
    void get();
    void su();
    void di();
    void pr();
    void dv();
};

inline void Operation::get()
{
    cout << "Enter first value:";
    cin >> a;
    cout << "Enter second value:";
    cin >> b;
}

inline void Operation::su()
{
    aa = a+b;
    cout << ": " << a+b << "\n";
}

inline void Operation::di()
{
    ss = a-b;
    cout << ": " << a-b << "\n";
}

inline void Operation::pr()
{
    mm = a*b;
    cout << ": " << a*b << "\n";
}

inline void Operation::dv()
{
    vv = a/b;
    cout << ": " << a/b << "\n";
}

int main()
{
    cout << "Program using inline function\n";
    Operation s;
    s.get();
    s.su();
    s.di();
    s.pr();
    s.dv();
    return 0;
}

Solution

: 60 : 30 : 675 : 3

What is the output of the following program?

#include <iostream>
using namespace std;

class Test
{
  private:
    int x;
  public:
    Test(int x = 0) { this->x = x; }
    void change(const Test  *t) { *this = *t; }
    void print() const { cout << "x = " << x << endl; }
};

int main()
{
    Test obj(5);
    Test* ptr = new Test (10);
    obj.change(ptr);
    obj.print();
    return 0;
}

Solution

x = 10

In the question above, the body of the constructor of Test reads: this->x = x; What does the first and second x refer to?
1. the first x is the class member variable
2. the second x is the class member variable
3. the first x is the function input argument
4. the second x is the function input argument
Solution

The first x is the class member variable, and the second is the function input argument

In the following program, is the line: obj1.setX(10).setY(20); correct? Why?

#include<iostream>
using namespace std;

class Test
{
  private:
    int x;
    int y;
  public:
    Test(int a = 0, int b = 0) { x = a; y = b; }
    Test& setX(int a) { x = a; return *this; }
    Test& setY(int b) { y = b; return *this; }
    void print() const { cout << "x = " << x << " y = " << y << endl; }
};

int main()
{
    Test obj1(5, 5);
    obj1.setX(10).setY(20);
    obj1.print();
    return 0;
}

Solution

Yes; When a reference to a non-local object is returned, the returned reference can be used to chain function calls on a single object. Here all calls modify the same object as the same object is returned by reference.

What is the output of the following C++ program?

#include <iostream>

class A
{
  public:
    A(int n = 0) : m(n) { std::cout << 'd'; }
    A(const A& a) : m(a.m) { std::cout << 'c'; }

  private:
    int m;
};

void f(const A& a1, const A& a2 = A()) { }

int main()
{
    A a(2), b;
    const A c(a), &d = c, e = b;
    b = d;
    A* p = new A(c), *q = &a;
    static_cast < void >(q);
    delete p;
    f(3);
    std::cout << std::endl;

    return 0;
}

Solution

ddcccdd

Self-test 1: C++ Class Basics

Self-test 1:
C++ Class Basics