C++ Programming Questions and Answers – Valarray

This set of C++ Programming Multiple Choice Questions & Answers (MCQs) focuses on “Valarray”.

1. What is Valarray in C++?
a) Container for efficient operations on an array
b) Container for efficient printing of the array
c) Container for efficient value conversion of array
d) Container for efficient type conversion of array
View Answer

2. Which of the following is correct about Valarray?
a) Supports element-wise mathematical operations
b) Slower than a normal array
c) Harder to use
d) Can have only integer Valarrays
View Answer

3. Which header file is required for using Valarray?
a) <array>
b) <Valarray>
c) <stl>
d) <algorithm>
View Answer

4. What is the use of apply() function in Valarray?
a) Returns new array after shifting elements by the given number
b) Returns the summation of all elements of the Valarray
c) Applies the manipulation provided to all the elements of the array
d) Returns new array after circular shifting elements by the given number
View Answer

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

#include <iostream>
#include <Valarray>
using namespace std;
int main()
{
	Valarray<int> varr = { 10, 2, 20, 1, 30 };
	for (int &x: varr) cout << x << " ";
	cout<<endl;
	varr = varr.apply([](int x){return x+=5;});
	for (int &x: varr) cout << x << " ";
	return 0;
}

a)

10 2 20 1 30 
15 7 25 6 35

b)

10 2 20 1 30 
10 7 25 6 35

c)

10 2 20 1 30 
15 7 20 1 35

d) 15 7 25 6 35
View Answer

6. What is the use of sum() function in Valarray?
a) Applies the manipulation provided to all the elements of the array
b) Returns the summation of all elements of Valarray
c) Returns new array after shifting elements by the given number
d) Returns new array after circular shifting elements by the given number
View Answer

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

#include <iostream>
#include <valarray>
using namespace std;
int main()
{
	valarray<int> varr = { 10, 2, 20, 1, 30 };
	cout<<"Sum of array: "<<varr.sum();
	return 0;
}

a) Sum of array: 20
b) Sum of array: 53
c) Sum of array: 12
d) Sum of array: 63
View Answer

8. What is the function of shift()?
a) Applies the manipulation provided to all the elements of the array
b) Returns the summation of all elements of Valarray
c) Returns new array after shifting elements by the given number
d) Returns new array after circular shifting elements by the given number
View Answer

9. Which of the following is correct about the shift?
a) Returns new array after shifting elements by the given number
b) Shifts the elements towards left if the argument supplied is positive
c) Shifts the elements towards the right if the argument supplied is negative
d) All of the mentioned
View Answer

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

#include <iostream>
#include <Valarray>
using namespace std;
int main()
{
	Valarray<int> varr = { 1, 2, 3, 4, 5 };
	for (int &x: varr) cout << x << " ";
	cout<<endl;
	varr = varr.shift(2);
	for (int &x: varr) cout << x << " ";
	return 0;
}

a)

1 2 3 4 5 
3 4 5 0 0 

b)

1 2 3 4 5 
0 0 3 4 5

c)

1 2 3 4 5 
1 2 3 4 5

d)

1 2 3 4 5 
3 4 5 1 2

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

#include <iostream>
#include <Valarray>
using namespace std;
int main()
{
	Valarray<int> varr = { 1, 2, 3, 4, 5 };
	for (int &x: varr) cout << x << " ";
	cout<<endl;
	varr = varr.shift(-3);
	for (int &x: varr) cout << x << " ";
	return 0;
}

a)

1 2 3 4 5 
1 2 0 0 0

b)

1 2 3 4 5 
0 0 0 1 2

c)

1 2 3 4 5 
3 4 5 1 2 

d)

1 2 3 4 5 
1 2 3 4 5

12. Which of the following is correct about shift() and cshift()?

1) shift() makes some values of Valarray equal to 0 after shifting by a non-zero number
2) cshift() makes some values of Valarray equal to 0 after shifting by a non-zero number

a) 2 only
b) 1 only
c) Both 1 and 2
d) Neither 1 nor 2
View Answer

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

#include <iostream>
#include <Valarray>
using namespace std;
int main()
{
	Valarray<int> varr = { 1, 2, 3, 4, 5 };
	for (int &x: varr) cout << x << " ";
	cout<<endl;
	varr = varr.cshift(-3);
	for (int &x: varr) cout << x << " ";
	return 0;
}

a)

1 2 3 4 5 
0 0 0 1 2

b)

1 2 3 4 5 
3 4 5 0 0 

c)

1 2 3 4 5 
3 4 5 1 2

d)

1 2 3 4 5 
0 0 0 0 0

14. Which function is used to swap two Valarray?
a) max()
b) min()
c) swap()
d) change()
View Answer

15. Which function is used to print the maximum element from Valarray?
a) change()
b) min()
c) swap()
d) max()
View Answer

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

To practice all areas of C++ language, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]