Arrays in C# - Dr. M AOUDE ULFG March 15, 2024 Quiz

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Questions and Answers

What is an array in C#?

A group of variables with different data types

A group of variables with the same type that are reference types (correct)

A single variable containing multiple values

An object of the System.Array class

How can you refer to a specific element in an array?

By specifying the data type of the element

By providing the name of the reference to the array and the element's index (correct)

By using the 'new' operator

By using the keyword 'element'

How do you create an array in C#?

By using the 'create' keyword

By declaring it as a constant literal

By using the 'new' operator and specifying the number of elements (correct)

By specifying different data types within square brackets

What class are arrays considered as in C#?

System.Array (B) Signup and view all the answers

What is the format for declaring an array in C#?

<code>type identifier = new type [integral value];</code> (B) Signup and view all the answers

Why are arrays typically created with the 'new' keyword in C#?

To instantiate an object of a user-defined class (B) Signup and view all the answers

In the given code snippet, what is the total value of all elements in the 'array'?

772 (C) Signup and view all the answers

What is the purpose of using the 'foreach' statement in C#?

To iterate through an array and provide read-only access (D) Signup and view all the answers

What is the main limitation of the iteration variable used in a 'foreach' loop?

It can only be used for assignment operations (B) Signup and view all the answers

When should the 'foreach' statement be used with arrays?

When every array element needs to be accessed (A) Signup and view all the answers

What does the 'var' keyword indicate in C#?

A variable of unknown type (B) Signup and view all the answers

Which of the following is NOT a valid use case for the 'foreach' statement with arrays?

Modifying array elements (B) Signup and view all the answers

What is the purpose of the 'params' keyword in C#?

Indicates the number of arguments that can vary in a method (A) Signup and view all the answers

In C#, where should the 'params' keyword be placed in the method heading?

It must be the last parameter listed (A) Signup and view all the answers

What does a parallel array refer to in C#?

Two or more arrays that have a relationship (C) Signup and view all the answers

How are arrays commonly used in classes in C#?

As fields or instance variables in classes (D) Signup and view all the answers

What is the output of the 'DisplayItems(1, 2, 3, 5);' method call?

[1, 2, 3] (A) Signup and view all the answers

What does the 'ModifyElement(array)' method attempt to do in C#?

Access a specific element in the array for modification (B) Signup and view all the answers

Study Notes

C# Arrays

An array is a data structure that allows you to store a collection of elements of the same data type.
To refer to a specific element in an array, you use its index, starting from 0 for the first element.
You can create an array in C# using the following format: data_type[] array_name = new data_type[size]; where data_type is the type of elements to store, array_name is the name of the array, and size is the number of elements.
Arrays in C# are considered as instances of the System.Array class.
Arrays are typically created with the 'new' keyword to allocate memory for the array elements according to the specified size.

Iterating Arrays in C#

The foreach statement is used to iterate over each element in a collection like an array without directly working with indices.
The iteration variable used in a foreach loop has a limitation: it can only read the elements, not modify them.
foreach statements should be used with arrays when you need to read all elements in an array sequentially without direct interaction with indices.

Keyword Usage

The 'var' keyword indicates that the variable's type is inferred from the value assigned to it. This improves code readability.
The foreach statement with arrays isn't suitable for tasks requiring modification of array elements while iterating.
The params keyword allows a method to accept a variable number of arguments of a specific type.
In C#, the params keyword should be placed before the parameter declaration in the method heading.

Advanced Array Concepts

A parallel array is a group of arrays that are used together to store related data. For example, string[] names = new string[3] and int[] ages = new int[3] are parallel arrays as each array stores data about a corresponding person.
Arrays are often used in classes in C# to store collections of data, like a class representing a student with fields for name, age, grades, which are all stored within arrays.

Code Snippet Analysis

In the code snippet DisplayItems(1, 2, 3, 5);, assuming DisplayItems sums all provided integers, the total value would be 11.
The ModifyElement(array) method likely attempts to modify one or more element in the provided array.

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Description

Test your knowledge on arrays in C# with this quiz. Questions cover topics such as iterating over arrays using foreach loop and calculating the total of array elements. Get ready to enhance your C# skills!