Single-dimensional array declaration in C Sharp (C#) - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a single-dimensional array in C#?

A single-dimensional array in C# is a collection of elements of the same type stored in a linear sequence. It is like a row of boxes where each box holds one value.

beginner

How do you declare a single-dimensional array of integers with 5 elements in C#?

You declare it like this: <br>int[] numbers = new int[5];<br>This creates an array named 'numbers' that can hold 5 integers.

beginner

What does the number inside the square brackets mean in new int[5]?

It means the size of the array, or how many elements it can hold. Here, the array can hold 5 integers.

beginner

How can you initialize a single-dimensional array with values at the time of declaration?

You can write: <br>int[] numbers = {1, 2, 3, 4, 5};<br>This creates an array with 5 elements and sets their values immediately.

beginner

What is the index of the first element in a C# array?

The first element's index is 0. Arrays in C# are zero-based, so counting starts from 0.

How do you declare a single-dimensional array of strings named 'names' with 3 elements in C#?

A string[] names = new string[3];

B string names = new string[3];

C string[] names = string[3];

D string names[] = new string(3);

Option A correctly declares a string array with 3 elements. The others have syntax errors.

What is the index of the last element in an array declared as int[] arr = new int[10];?

A 1

B 9

C 0

D 10

Since indexing starts at 0, the last element is at index 9 for an array of size 10.

Which of the following initializes an array with values 10, 20, 30 in C#?

A int[] nums = new int[3] {10, 20, 30};

B int nums[] = new int{10, 20, 30};

C int[] nums = {10, 20, 30};

D int nums = new int[3] {10, 20, 30};

Options A and C correctly declare and initialize the array with the given values. The others have syntax errors.

What happens if you try to access an array element with an index outside its range?

A The program ignores the request.

B It returns null.

C It returns the last element.

D You get a runtime error called IndexOutOfRangeException.

Accessing outside the array bounds causes a runtime error in C#.

Which keyword is used to create a new array instance in C#?

A new

B create

C array

D init

The 'new' keyword is used to create new array instances.

Explain how to declare and initialize a single-dimensional array of integers with 4 elements in C#.

Think about the syntax: type[], name, new, size or values.

Describe what zero-based indexing means in the context of C# arrays.

Imagine counting boxes starting at zero.