What is a variable in programming?

A variable in programming is a storage location that is given a symbolic name, allowing programmers to store data and refer to it throughout their code. This naming enables readability and makes the code easier to understand and manage. The variable can hold different values over time and can be manipulated within the program, which provides flexibility. For example, if you define a variable called age, you can set it to different numeric values as the program runs, unlike a fixed value which would remain constant.

The concept of a variable is crucial as it facilitates dynamic data manipulation, allowing for more complex and responsive programming structures. In contrast, a fixed value does not allow for change, a loop structure serves a different purpose of repeating code execution, and comments are used solely for the clarification of code without affecting its execution or logic. Therefore, the essence of a variable lies in its ability to act as a mutable reference to data, making it foundational in programming languages like Java.