C++ Programming Questions and Answers – Complex Library – 2

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This set of C++ Programming Multiple Choice Questions & Answers (MCQs) focuses on “Complex Library – 2”.

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

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#include <iostream>
#include <complex>
using namespace std;
int main()
{
	complex <double> cn(3.0, 5.0);
	cout<<"Complex number with magnitude "<<abs(cn)<<" 
        and phase angle "<<arg(cn)<<" is: 
        "<<polar(abs(cn), arg(cn))<<endl;
	return 0;
}

a) Complex number with magnitude 5.83095 and phase angle 1.03038 is: (3,5)
b) Complex number with magnitude 1.03038 and phase angle 5.83095 is: (3,5)
c) Complex number with magnitude 5.83095 and phase angle 5.83095 is: (3,5)
d) Complex number with magnitude 1.03038 and phase angle 1.03038 is: (3,5)
View Answer

Answer: a
Explanation: In this program we are trying to costruct a complex number using polar() function of <complex> header.

2. Which function is used to calculate the norm of a complex number?
a) abs()
b) norm()
c) mod()
d) square_sum()
View Answer

Answer: b
Explanation: <complex> header provides norm() function to calculate the norm of a complex number.

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

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#include <iostream>
#include <complex>
using namespace std;
int main()
{
	complex <double> cn(3.0, 4.0);
	cout<<"Norm is: "<<norm(cn)<<endl;
	return 0;
}

a) 9
b) 16
c) 25
d) 5
View Answer

Answer: c
Explanation: In this program we are trying to calculate the norm of a complex number using norm() function of <complex> header.

4. Which function is used to calculate the conjugate of a complex number?
a) conj()
b) reverse()
c) opp()
d) find_conj()
View Answer

Answer: a
Explanation: <complex> header provides conj() function to calculate the conjugate of a complex number.

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

#include <iostream>
#include <complex>
using namespace std;
int main()
{
	complex <double> cn(3.0, 4.0);
	auto cnj = conj(cn);
	cout<<"Conjugate of "<<real(cn)<<"+("<<imag(cn)<<")i is: "<<real(cnj)<<"
        +("<<imag(cnj)<<")i"<<endl;
	return 0;
}

a) Conjugate of 3+(4)i is: 3+(4)i
b) Conjugate of 3+(4)i is: 3-(-4)i
c) Conjugate of 3+(4)i is: 3-(+4)i
d) Conjugate of 3+(4)i is: 3+(-4)i
View Answer

Answer: d
Explanation: The complex conjugate of a+ib is a-ib so conj() of 3+4i = 3-4i or conj(complex(3,4)) = complex(3,-4).
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6. What is the use of proj() function?
a) Used to calculate the argument of a complex number
b) Used to calculate the conjugate of a complex number
c) Used to calculate the negative of a complex number
d) Used to calculate the projection of a complex number
View Answer

Answer: d
Explanation: <complex> header provides proj() function to calculate the projection of a complex number a + ib.

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

#include <iostream>
#include <complex>
using namespace std;
int main()
{
	complex <double> cn(3.0, 4.0);
	cout<<"proj"<<cn<<" : "<<proj(cn)<<endl;
	return 0;
}

a) proj(3,4) : (3,4)
b) proj(3,4) : (4,3)
c) proj(3,4) : (-3,-4)
d) proj(3,4) : (-3,4)
View Answer

Answer: a
Explanation: In this program we are trying to calculate the projection of a complex number complex(3,4) using proj() function of <complex> header the answer to which is (3,4).
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8. What is the use of log() function in a complex?
a) To calculate the log of the imaginary part of a complex number
b) To calculate the log of rethe al part of a complex number
c) To calculate the log of a complex number
d) To calculate the log of the argument of a complex number
View Answer

Answer: c
Explanation: <complex> header provides log() function to calculate the logarithm of a complex number a + ib.

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

#include <iostream>
#include <complex>
using namespace std;
int main()
{
	complex <double> cn(3.0, 4.0);
	cout<<log(cn)<<endl;
	return 0;
}

a) 1.60944
b) (1.60944,0.927295)
c) 0.927295
d) 1.60944 + 0.927295
View Answer

Answer: b
Explanation: In this program we are trying to calculate the logarithm of a complex number complex(3,4) using log() function of <complex> header the answer to which is (1.60944,0.927295).

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

#include <iostream>
#include <complex>
using namespace std;
int main()
{
	complex <double> cn(3.0, 4.0);
	cout<<sin(cn)<<endl;
	return 0;
}

a) (3.85374,-27.0168)
b) 3.85374
c) -27.0168
d) 3.85374 – 27.0168
View Answer

Answer: a
Explanation: In this program we are trying to calculate the sine of a complex number complex(3,4) using sin() function of <complex> header the answer to which is (3.85374,-27.0168).

Sanfoundry Global Education & Learning Series – C++ Programming Language.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn