In most programming languages, const and readonly are keywords used to declare variables that cannot be modified after initialization.
However, the usage of const and readonly variables’ usage may vary depending on the language and context.
In C#, constis a keyword that declares a constant value that is computed at compile-time and can never be changed.
In C#, readonlyis a keyword that declares a value that can be assigned only once and can be determined at run-time.
Here are some key differences between the const and readonly variables in C#,
- const values must be initialized when declared, and the value cannot be modified later. On the other hand, readonly values can be initialized when declared or in a constructor, and the value can be modified only within the constructor.
- const values are implicitly static, meaning they belong to the type rather than any instance of the type. Read-only values, on the other hand, can be instance-specific or static.
- const values can be used in any context where a constant expression is allowed, such as array lengths, switch cases, and attribute arguments. read-only values, on the other hand, are just regular variables that cannot be modified once set.
In summary, const is used to declare compile-time constants that cannot be changed, while readonly is used to declare run-time constants that can be changed only within a constructor.