C# Const: Usage & Best Practices

In C#, the keyword “const” is used to declare constant variables, which are identifiers in a program with fixed values that cannot be changed.

The usage of constants is as follows:

1. Declare constants: Use the const keyword to declare constants and initialize them at the time of declaration. The value of constants remains unchanged throughout the duration of the program execution.

const int maxScore = 100;
const string appName = "MyApp";

1. Constants can be of any value type, reference type, or string type in C# with the limitation of types.

const int maxAge = 18;
const double pi = 3.14159;
const string welcomeMessage = "Welcome to my application";

1. Constants are evaluated at compile time, their values are determined beforehand allowing for optimization during compilation. This suggests that during compilation, the values of constants will be replaced with their actual values.

const int result = 10 * 5; // 在编译时求值，result的值将为50

1. Constant naming convention: According to the C# naming convention, constants are typically named using uppercase letters and separated by underscores.

const int MAX_SCORE = 100;
const string APP_NAME = "MyApp";

It should be noted that the value of a constant must be determined at the time of declaration and cannot be changed elsewhere in the program. Constants are typically used to represent fixed values that will not be altered, such as mathematical constants, configuration settings, or common values within a program.