C# Constants

C# Constants

Constants in C# are variables whose value cannot be changed once it is assigned. They are useful for storing fixed values like PI, tax rates, or configuration values.

Declaring Constants

Use the const keyword.

const int MAX_VALUE = 100;

  • const → keyword

  • int → data type

  • MAX_VALUE → constant name

  • 100 → value

⚠ Once assigned, the value cannot be modified.

 Example


 

 Why Use Constants?

  • Prevent accidental value changes

  • Improve code readability

  • Easier maintenance

  • Faster execution (compile-time constant)

 Naming Convention

✔ Use UPPERCASE letters
✔ Use underscore (_) for multiple words



 

 Constants with Different Data Types



 

 Constant vs Variable

Feature Constant (const) Variable
Value change ❌ Not allowed ✅ Allowed
Assignment Only once Multiple times
Use case Fixed values Changing data

 const vs readonly

const

  • Compile-time constant

  • Value must be known at compile time

const int SPEED = 60;

readonly

  • Runtime constant

  • Value set in constructor


 

 Summary

✔ Constants store fixed values
✔ Use const keyword
✔ Cannot be modified
✔ Follow uppercase naming convention
✔ Use readonly for runtime constants

👉 What would you like next?

  • C# Data Types

  • C# Operators

  • C# Type Casting

  • C# Input

  • C# Control Statements

You may also like...