What is the purpose of a function in programming?

A function in programming serves the primary purpose of encapsulating a set of related statements that can be executed when the function is called. This encapsulation allows for better organization of code, making it modular and reusable. When a function is defined, it can include parameters and return values, enabling it to accept inputs and provide outputs, which further enhances its utility. This capability also helps to reduce redundancy in code; once a function is written, it can be invoked multiple times throughout a program without needing to rewrite the sequence of statements.

While declaring new variables, performing data input/output operations, and optimizing code performance may be associated with functions or be tasks that functions can help manage, they do not capture the fundamental role of a function itself. The essence of a function lies in its ability to group code into a single logical block that can be easily managed and maintained.