Learn Declaring and Initializing Arrays

Prerequisites

C# Basics

Arrays are a fundamental concept in C# that allow you to store multiple values of the same type under a single variable name. They are useful when you need to manage collections of data, such as a list of numbers or words, without creating separate variables for each item. In C#, arrays store data in a fixed-size, ordered sequence, which means every element can be accessed by its numerical index, starting from zero.

Definition

An array is a fixed-size, ordered collection of elements of the same type.

Program.cs


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using System;

namespace ConsoleApp
{
    public class Program
    {
        public static void Main(string[] args)
        {
            // Declare an integer array with 3 elements
            int[] numbers = new int[3];

            // Assign values to each element
            numbers[0] = 10;
            numbers[1] = 20;
            numbers[2] = 30;

            // Declare and initialize a string array with 2 elements
            string[] names = new string[2];
            names[0] = "Alice";
            names[1] = "Bob";

            // Print the arrays
            Console.WriteLine("Integer array:");
            Console.WriteLine(numbers[0]);
            Console.WriteLine(numbers[1]);
            Console.WriteLine(numbers[2]);

            Console.WriteLine("String array:");
            Console.WriteLine(names[0]);
            Console.WriteLine(names[1]);
        }
    }
}

In the code above, you first declare an integer array called numbers with a size of 3. This means the array can hold exactly three integers. When you create an array with new int[3], each element is automatically set to the default value for that type—in this case, 0 for integers. You then assign values to each index: numbers[0] = 10, numbers[1] = 20, and numbers[2] = 30. Similarly, you declare a string array named names with two elements and assign values to both. Arrays in C# are always zero-indexed, so the first element is at index 0. If you try to access an index outside the range (for example, numbers[3]), you will get a runtime error.

Program.cs


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// File: Program.cs
using System;

namespace ConsoleApp
{
    public class Program
    {
        public static void Main(string[] args)
        {
            // Initialize an integer array with explicit values
            int[] scores = { 85, 92, 78, 90 };

            // Initialize a string array with explicit values
            string[] fruits = { "Apple", "Banana", "Cherry" };

            // Print all elements and the array length
            Console.WriteLine("Scores array:");
            for (int i = 0; i < scores.Length; i++)
            {
                Console.WriteLine(scores[i]);
            }
            Console.WriteLine("Scores array length: " + scores.Length);

            Console.WriteLine("Fruits array:");
            for (int i = 0; i < fruits.Length; i++)
            {
                Console.WriteLine(fruits[i]);
            }
            Console.WriteLine("Fruits array length: " + fruits.Length);
        }
    }
}

1. What is the primary characteristic of an array in C#?

2. Which of the following is a correct way to declare an array of 5 integers?

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 1

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Prerequisites

C# Basics

Definition

An array is a fixed-size, ordered collection of elements of the same type.

Program.cs


              12345678910111213141516171819202122232425262728293031323334
            
using System;

namespace ConsoleApp
{
    public class Program
    {
        public static void Main(string[] args)
        {
            // Declare an integer array with 3 elements
            int[] numbers = new int[3];

            // Assign values to each element
            numbers[0] = 10;
            numbers[1] = 20;
            numbers[2] = 30;

            // Declare and initialize a string array with 2 elements
            string[] names = new string[2];
            names[0] = "Alice";
            names[1] = "Bob";

            // Print the arrays
            Console.WriteLine("Integer array:");
            Console.WriteLine(numbers[0]);
            Console.WriteLine(numbers[1]);
            Console.WriteLine(numbers[2]);

            Console.WriteLine("String array:");
            Console.WriteLine(names[0]);
            Console.WriteLine(names[1]);
        }
    }
}

Program.cs


              123456789101112131415161718192021222324252627282930313233
            
// File: Program.cs
using System;

namespace ConsoleApp
{
    public class Program
    {
        public static void Main(string[] args)
        {
            // Initialize an integer array with explicit values
            int[] scores = { 85, 92, 78, 90 };

            // Initialize a string array with explicit values
            string[] fruits = { "Apple", "Banana", "Cherry" };

            // Print all elements and the array length
            Console.WriteLine("Scores array:");
            for (int i = 0; i < scores.Length; i++)
            {
                Console.WriteLine(scores[i]);
            }
            Console.WriteLine("Scores array length: " + scores.Length);

            Console.WriteLine("Fruits array:");
            for (int i = 0; i < fruits.Length; i++)
            {
                Console.WriteLine(fruits[i]);
            }
            Console.WriteLine("Fruits array length: " + fruits.Length);
        }
    }
}

1. What is the primary characteristic of an array in C#?

2. Which of the following is a correct way to declare an array of 5 integers?

Everything was clear?

Thanks for your feedback!

Section 1. Chapter 1