C++ Programming Questions and Answers – Lambda Expressions

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

1. What is lambda expression in C++?
a) A technique of C++ that allows us to write inline functions without a name
b) A technique of C++ that allows us to write overloaded functions
c) A technique of C++ that allows us to write functions that are called more than once
d) A technique of C++ that allows us to write functions without parameters
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2. What is the syntax of defining lambda expression?
a) [capture clause](parameters) -> return_type { body of the function }
b) [parameters](capture clause) -> return_type { body of the function }
c) [parameters:capture clause]() -> return_type { body of the function }
d) [capture clause:parameters]() -> return_type { body of the function }
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[capture clause](parameters) -> return_type 
{ 
	the body of the function 
}

3. What is the correct statement about lambda expression?
a) The return type of lambda expression can be neglected in some cases
b) The return type of lambda expression must be specified in all cases
c) Lambda expression should be very large functions
d) Lambda expression is also available in C
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4. In how many ways we can capture the external variables in the lambda expression?
a) 1
b) 2
c) 3
d) 4
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5. Which of the following operator is used to capture all the external variable by reference?
a) &
b) =
c) *
d) &&
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6. Which of the following operator is used to capture all the external variable by value?
a) &
b) =
c) *
d) &&
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7. Which is the correct syntax of capturing a variable ‘X’ by reference and other variable ‘Y’ by value in lambda expression?
a) [&X, Y]
b) [X, &y]
c) [X, Y]
d) [&x, &Y]
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8. What will be the output of the following C++ code?

#include<iostream>
using namespace std;
int main()
{
	int x = 5;
	auto check = []() -> bool 
        {
		if(x == 0)
			return false;
		else
			return true;
	};
	cout<<check()<<endl;
	return 0;
}

a) 1
b) 0
c) Error
d) Segmentation fault
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9. What will be the output of the following C++ code?

#include<iostream>
using namespace std;
int main()
{
	int a = 5;
	auto check = [](int x) 
        {
		if(x == 0)
			return false;
		else
			return true;
	};
	cout<<check(a)<<endl;
	return 0;
}

a) 0
b) 1
c) Error
d) Segmentation fault
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10. What will be the output of the following C++ code?

#include<iostream>
using namespace std;
int main()
{
	int a = 5;
	auto check = [=]() 
        {
		a = 10;
	};
	check();
	cout<<"Value of a: "<<a<<endl;
	return 0;
}

a) Value of a: 5
b) Value of a: 10
c) Error
d) Segmentation fault
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11. What will be the output of the following C++ code?

#include<iostream>
using namespace std;
int main()
{
	int a = 5;
	auto check = [&]() 
        {
		a = 10;
	};
	check();
	cout<<"Value of a: "<<a<<endl;
	return 0;
}

a) Value of a: 5
b) Value of a: 10
c) Error
d) Segmentation fault
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12. What will be the output of the following C++ code?

#include<iostream>
using namespace std;
int main()
{
	int a = 5;
	int b = 5;
	auto check = [&a]() 
        {
		a = 10;
		b = 10;
	}
	check();
	cout<<"Value of a: "<<a<<endl;
	cout<<"Value of b: "<<b<<endl;
	return 0;
}

a) Value of a: 5
b) Value of a: 10
c) Error
d) Segmentation fault
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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.

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