C# Lambdas Quiz

Welcome to the C# Anonymous Methods, Lambdas, and Local Functions Quiz! This quiz will test your understanding of advanced C# concepts like anonymous methods, lambda expressions, and local functions. These features help you write more concise, flexible, and reusable code. You will explore how each of these techniques works, their differences, and when to use them for optimal efficiency.

What are local functions in C#?

Lambda expressions that return integers.

Functions that only exist at runtime.

Named methods declared inside other methods.

Functions that must be declared at the start of a program.

None

Which of the following is a valid lambda expression that accepts no parameters?

(s) => s.ToUpper()

() => &quotHello&quot

(int a, int b) => a + b

(name) => name.ToLower()

None

Why does Visual Studio often suggest converting lambdas to local functions?

Local functions are easier to use with strings.

Local functions are more efficient and provide direct access to local variables.

Local functions are faster than lambdas in every scenario.

Lambdas are considered deprecated in modern C#.

None

Which of the following situations would benefit most from using a local function instead of a lambda?

When you need to call multiple methods.

When you need a concise one-line expression.

When you need access to local variables and plan to use recursion.

When you need to work with large datasets.

None

What will the following local function return?

double USDToEuro(double dollars) => exchangeRate * dollars;

It will return an error because local functions cannot use lambdas.

It will return the exchange rate itself.

It will return the product of the exchangeRate and the dollars passed.

It will return a string representation of the conversion.

None

Which of the following allows lambdas and local functions to be called recursively?

Only lambdas can be recursive, local functions cannot.

Local functions and lambdas can both call themselves recursively.

Neither lambdas nor local functions can be recursive.

Only local functions can be recursive, lambdas cannot.

None

What advantage do local functions have over lambdas?

They are more efficient since they do not require delegate allocations.

They can access only global variables.

They require fewer lines of code.

They are faster in asynchronous operations.

None

How do you declare a local function that uses the => operator?

You declare the local function normally and use the => operator for concise expressions.

The => operator can only be used in global functions.

You must use a delegate keyword with the => operator.

Local functions cannot use the => operator.

None

Which of the following is a recursive local function?

A local function that takes no parameters.

A lambda that returns a method reference.

A local function that calls itself to perform repeated tasks.

A function that always returns a string.

None

10.

What is one key difference between lambdas and local functions?

Local functions have direct access to variables in the containing method, while lambdas do not.

Lambdas cannot return values, but local functions can.

Lambdas can be called from outside the method, while local functions cannot.

Local functions are always asynchronous, while lambdas are not.

None

11.

How do you declare a local function in C#?

By using the ‘local’ keyword.

By declaring the function at the top of the class.

By using the ‘static’ keyword inside the method.

By declaring a method inside another method.

None

12.

What is one advantage of using local functions?

They have direct access to local variables within the containing method.

They can be accessed from outside the class.

They must return a boolean value.

They are automatically asynchronous.

None

13.

What is an anonymous method in C#?

A method that does not accept parameters.

A method declared inline using the delegate keyword.

A method that only accepts one parameter.

A method that must have a name.

None

14.

How can you create a lambda expression that accepts no parameters?

Use the ‘params’ keyword before the expression.

You cannot create a lambda expression with no parameters.

Use the void keyword before the lambda: void => expression;

Use empty parentheses for the input parameters: () => expression;

None

15.

What will the following lambda expression return?

s => s.ToLower();

It will return an error because no return type is specified.

It will return the length of the input string.

It will return the lowercase version of the input string.

It will return the uppercase version of the input string.

None

16.

What is a key advantage of lambda expressions over anonymous methods?

Lambda expressions provide a more concise syntax.

Lambda expressions are automatically asynchronous.

Lambda expressions can only accept integer parameters.

Lambda expressions cannot return values.

None

17.

How can you pass multiple parameters to a lambda expression?

By listing them after the return type.

By separating them with a colon.

By using the ‘params’ keyword.

By enclosing the parameters in parentheses.

None

18.

What is a statement lambda?

A lambda that only works with loops.

A lambda that must return a boolean.

A lambda that contains multiple statements in a block.

A lambda that cannot return any value.

None

19.

What is an expression lambda?

A lambda that only works with arrays.

A lambda that accepts no parameters.

A lambda where the body contains a single expression.

A lambda that returns multiple values.

None

20.

Which operator is used to define a lambda expression in C#?

None

21.

What is a lambda expression in C#?

A method that must return a string.

A delegate that only works with integers.

A method that cannot accept parameters.

A more concise way of writing anonymous methods.

None

22.

How would you call an anonymous method assigned to a delegate?

By invoking the delegate variable like a method.

By calling the method name directly.

By using the call() function.

By invoking it with a special keyword.

None

23.

What is the key difference between a delegate and an anonymous method?

An anonymous method does not reference an existing named method.

Delegates are faster than anonymous methods.

Anonymous methods cannot have return values.

A delegate cannot store a method reference.

None

24.

Which syntax is used to declare an anonymous method in C#?

delegate (parameters) { //code };

lambda => expression;

anonymous method() { //code };

method (parameters) { //code };

None

Time’s up

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