C++ Programming Questions and Answers – Complex Number Type

C++ interview questions and answers focuses on “Complex Number Type”. One shall practice these interview questions to improve their C++ programming skills needed for various 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++ interview questions come with the detailed explanation of the answers which helps in better understanding of C++ concepts.

C++ interview questions on “Complex Number Type” along with answers, explanations and/or solutions:

Q 1. Which header file is used to declare the complex number?
A. complexnum
B. complex number
C. complex
D. complexarg

Show Answer

Answer:-C. complex

Explanation

header file is used for declaring a complex number in C++.

Q 2. How to declare the complex number?
A. (3, 4)
B. complex(3, 4)
C. (3, 4i)
D. (3, 4g)

Show Answer

Answer:-B. complex(3, 4)

Explanation

We can declare the complex number by using complex(3,4) where 3 is a real number and 4 is imaginary part.

Q 3. How many real types are there in complex numbers?
A. 1
B. 2
C. 3
D. 4

Show Answer

Answer:-C. 3

Explanation

There are three real types in complex numbers. They are float complex, double complex, long double complex.

Q 4. Which of the following is not a function of complex values?
A. real
B. imag
C. norm
D. cartesian

Show Answer

Answer:-D. cartesian

Explanation

Real is used for returning real part, imag for imaginary part and norm for calculating norm of a complex number. There is no such function Cartesian in complex header file.

Q 5. What will be the output of the following C++ code?

#include <iostream>

#include <complex>

using namespace std;

int main()

{

complex<double> c_double(2, 3);

complex<int> c_int(4, 5);

c_double *= 2;

c_double = c_int;

cout << c_double;

return 0;

}

A. (2, 3)
B. (4, 5)
C. (8, 15)
D. (8, 10)

Show Answer

Answer:-B. (4, 5)

Explanation

We are just copying the value of c_int into c_double, So it’s printing as (4,5). Output: $ g++ comp1.cpp $ a.out (4,5)

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

#include <iostream>

#include <complex>

using namespace std;

int main()

{

complex<int> i(2, 3);

i = i * 6 / 3;

cout << i;

return 0;

}

A. (2, 3)
B. (4, 6)
C. (6, 12)
D. (6, 15)

Show Answer

Answer:-B. (4, 6)

Explanation

We are multiplying the complex number by 2. Output: $ g++ comp2.cpp $ a.out (4,6)

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

#include <iostream>

#include <complex>

using namespace std;

int main()

{

complex<double> c1(4.0,3.0);

cout << “c1: ” << c1;

complex<float> c2(polar(5.0,0.75));

cout << c1 + complex<double>(c2.real(),c2.imag());

return 0;

}

A. c1: (4,3)(7.65844,6.40819)
B. c1: (4,3)(7,6)
C. both c1: (4,3)(7.65844,6.40819) & c1: (4,3)(7,6)
D. c1: (5,3)(7,6)

Show Answer

Answer:-A. c1: (4,3)(7.65844,6.40819)

Explanation

We are adding the two complex numbers and printing the result. Output: $ g++ comp3.cpp $ a.out c1: (4,3)(7.65844,6.40819)

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

#include <iostream>

#include <complex>

using namespace std;

int main()

{

complex<double> c1(4.0, 3.0);

complex<float> c2(polar(5.0, 0.75));

cout << (c1 += sqrt(c1)) << endl;

return 0;

}

A. (4.0, 3.0)
B. (6.12132, 3.70711)
C. (5.0, 0.75)
D. (5.0, 3.75)

Show Answer

Answer:-B. (6.12132, 3.70711)

Explanation

In this program, we are adding both complex number and finding the square root of it. Output: $ g++ comp4.cpp $ a.out (6.12132,3.70711)

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

#include <iostream>

#include <complex>

using namespace std;

int main ()

{

complex<double> mycomplex (20.0, 2.0);

cout << imag(mycomplex) << endl;

return 0;

}

A. 2
B. 20
C. 40
D. 30

Show Answer

Answer:-A. 2

Explanation

imag part will return the imaginary part of the complex number. Output: $ g++ comp5.cpp $ a.out 2

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

#include <iostream>

#include <complex>

using namespace std;

int main()

{

complex<double> c1(4.0, 16.0), c2;

c2 = pow(c1, 2.0);

cout << c2;

return 0;

}

A. (-240, 128)
B. (240, 128)
C. (240, 120)
D. (240, -122)

Show Answer

Answer:-A. (-240, 128)

Explanation

In this program, we are finding the square of the complex number. Output: $ g++ comp.cpp $ a.out (-240,128)