C# Constant

A variable can declare as constant by using the C# keyword const. A variable declared as the constant should assign its value at its declaration time.

This value assigned to the constant variable is immutable (cannot change throughout the program’s execution life cycle) and called “compile-time”.

The const keyword applies to any built-in value type, enum, a string literal, or a reference type. Let us see an example of C# code using a constant variable.

using System;

namespace CSharp_Tutorial
{
    class Program
    {
        static void Main()
        {
            const double pi = 3.14159;
            Console.WriteLine("Pi value is {0} ", pi);
        }
    }
}

OUTPUT

In this C# example, pi is a double variable whose value is 3.14159.

Hence pi will declare as a const variable. The number remains the same throughout the program’s execution life cycle.