Declaring Constants

Constants are like variables, but their value is set once at the time of declaration and cannot be changed later.

They are helpful in making the code more understandable by clearly indicating which values are fixed and should not change throughout the program. Additionally, using constants helps prevent accidental changes to data, thereby reducing bugs in the code.

To declare a constant, we use a syntax similar to variable declaration, but we add the keyword const before it:

main


              12345678910111213
            
using System;

namespace ConsoleApp
{
    internal class Program
    {
        static void Main(string[] args)
        {
			const int myVar = 10;
			Console.WriteLine(myVar);
        }
    }
}

If we try to modify a constant, the compiler will show an error:

main


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using System;

namespace ConsoleApp
{
    internal class Program
    {
        static void Main(string[] args)
        {
			const int myVar = 10;
			myVar = 20; 
          // Error: The left-hand side of an assignment must be a variable, property or indexer.
        }
    }
}

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Section 2. Chapter 10

C# Basics

Declaring Constants

Complete the code for declaring a constant called pi having a value of 3.14:

Complete the code for declaring a constant called `pi` having a value of `3.14`: