What is a key feature of a constant value in programming?

A key feature of a constant value in programming is that it provides stability by not changing throughout the program runtime. Constants are defined to hold a particular value that, once set, cannot be altered by the program. This characteristic is crucial for maintaining predictability in code execution because it allows programmers to rely on certain values remaining the same, which is especially important when those values represent fixed parameters, configuration settings, or specific thresholds within the application.

The use of constants can prevent unintended modifications to important values, which can help reduce bugs and improve overall program reliability. By defining values as constants, developers signal their intent clearly, making the code more understandable and maintainable. In contrast, values that change during execution can lead to confusion and errors, particularly if they're modified in ways that are difficult to track throughout the program's flow.