C++ Programming Questions and Answers – Conversion Operators

C++ Multiple Choice Questions focuses on “Conversion Operators”. One shall practice these questions to improve their C++ programming skills needed for various interviews (campus interviews, walk-in interviews, company interviews), placements, entrance exams and other competitive exams. These questions can be attempted by anyone focusing on learning C++ programming language. They can be a beginner, fresher, engineering graduate or an experienced IT professional. Our C++ questions comes with a detailed explanation of the answers which helps in better understanding of C++ concepts.

C++ Questions & Answers focuses on “Conversion Operators” along with answers, explanations and/or solutions:

Q 1. What is the return type of the conversion operator?
A. void
B. int
C. float
D. no return type

Show Answer

Answer:-D. no return type

Explanation

Conversion operator doesn’t have any return type not even void.

Q 2. Why we use the “dynamic_cast” type conversion?
A. to be used in low memory
B. result of the type conversion is a valid
C. result of the type conversion is an invalid
D. it is used for storage

Show Answer

Answer:-B. result of the type conversion is a valid

Explanation

It is used to check that operators and operands are compatible after conversion.

Q 3. How many parameters does a conversion operator may take?
A. 0
B. 1
C. 2
D. as many as possible

Show Answer

Answer:-A. 0

Explanation

0 parameters does a conversion operator will take.

Q 4. How are types therein user-defined conversion?
A. 1
B. 2
C. 3
D. 4

Show Answer

Answer:-B. 2

Explanation

There are two types of user-defined conversions. They are conversion by the constructor, Conversion functions.

Q 5. Pick out the correct syntax of operator conversion.
A. operator float()const
B. operator float()
C. operator const
D. operator const()

Show Answer

Answer:-A. operator float()const

Explanation

The syntax of operator conversion is operator float()const.

Q 6. What will be the output of the following C++ code?

#include <iostream>

using namespace std;

class sample1

{

float i, j;

};

class sample2

{

int x, y;

public:

sample2 (int a, int b)

{

x = a;

y = b;

}

int result()

{

return x + y;

}

};

int main ()

{

sample1 d;

sample2 * padd;

padd = (sample2*) &d;

cout<< padd->result();

return 0;

}

A. 20
B. runtime error
C. random number
D. runtime error or random number

Show Answer

Answer:-D. runtime error or random number

Explanation

As it assigns to a reference to an object of another incompatible type using explicit type-casting. Output: $ g++ con.cpp $ a.out 14032334

Q 7. What will be the output of the following C++ code?

#include <iostream>

using namespace std;

class sample

{

public:

sample(int i) : m_i(i) { }

public:

int operator()(int i = 0) const

{

return m_i + i;

}

operator int () const

{

return m_i;

}

private:

int m_i;

friend int g(const sample&);

};

int f(char c)

{

return c;

}

int main()

{

sample f(2);

cout << f(2);

return 0;

}

A. 3
B. 4
C. 5
D. 6

Show Answer

Answer:-B. 4

Explanation

In this program, we are adding its value with it itself, So only we got the output as 4. Output: $ g++ con1.cpp $ a.out 4

Q 8. What will be the output of the following C++ code?

#include <iostream>

#include <cmath>

using namespace std;

class Complex

{

private:

double real;

double imag;

public:

Complex(double r = 0.0, double i = 0.0) : real(r), imag(i)

{}

double mag()

{

return getMag();

}

operator double ()

{

return getMag();

}

private:

double getMag()

{

return sqrt(real * real + imag * imag);

}

};

int main()

{

Complex com(3.0, 4.0);

cout << com.mag();

cout << com;

return 0

}

A. 4 5
B. 5 5
C. 6 6
D. 7 5

Show Answer

Answer:-B. 5 5

Explanation

In this program, we are calculating the magnitude value by two ways. Output: $ g++ con3.cpp $ a.out 55

Q 9. What will be the output of the following C++ code?

#include <iostream>

#include <string>

using namespace std;

class test

{

public:

operator string ()

{

return “Converted”;

}

};

int main()

{

test t;

string s = t;

cout << s << endl;

return 0;

}

A. converted
B. error
C. run time error
D. convertedconverted

Show Answer

Answer:-A. converted

Explanation

In this program, We casted the string to the object of the class. Output: $ g++ con4.cpp $ a.out converted

Q 10. What will be the output of the following C++ code?

#include <iostream>

using namespace std;

int main()

{

double a = 21.09399;

float b = 10.20;

int c ;

c = (int) a;

cout << c ;

c = (int) b;

cout << c ;

return 0;

}

A. 1210
B. 1210
C. 21
D. 2110

Show Answer

Answer:-D. 2110

Explanation

In this program, we casted the data type to integer. Output: $ g++ con5.cpp $ a.out 2110