What is a constant in programming?

A constant in programming refers to an identifier that holds a value which cannot be altered during the execution of a program. Constants are used when there is a need to ensure that certain values remain fixed throughout the program, enhancing readability and reducing the chance of errors that might arise from unintentional modifications.

For example, when you define a constant for mathematical values like Pi in a Java program, it allows you to use this value without worrying that it will change at some point in your code. In Java, constants are typically declared using the final keyword, which prevents any accidental reassignment.

Understanding the role of constants is crucial as they help in maintaining code stability and clarity, especially in larger programs where the same value might be used multiple times. This clarity helps other developers, or even yourself in the future, to understand the code better when constants are employed appropriately.