What key role do functions play in programming?

Functions play a crucial role in programming by promoting code reuse and allowing developers to return values for further processing. When you define a function, you encapsulate a specific task or set of instructions that can be called multiple times throughout your program, which reduces redundancy and streamlines code maintenance. This reusability of code saves time and effort because once a function is written and tested, it can be called wherever needed without rewriting the same code.

Additionally, functions can return values, which allows for the output of data that can then be used elsewhere in the program. This feature facilitates the flow of information, enabling more effective handling of tasks as the returned data can affect subsequent operations or calculations. By using functions effectively, programmers can build cleaner, more organized, and more efficient code bases.