What is the key difference between a procedure and a function in programming?

A function is designed to return a value after performing its intended operations, which is a fundamental aspect of its purpose in programming. This allows for operations to be encapsulated in a way that not only performs computations but also sends back results to the calling context. Functions typically operate on input parameters and generate an output based on those inputs, making them essential for reusable and modular code.

On the other hand, a procedure is primarily intended to perform a task or a series of actions but is not structured to return a value. Procedures might modify variables, change the program state, or perform input/output actions, but the main difference lies in their lack of a return capability. This distinction is crucial in different programming paradigms, where understanding the roles of functions and procedures allows developers to write more efficient and organized code.

The other options you referenced do not accurately describe the specific characteristics of procedures and functions within programming. Functions inherently have the ability to return values, while procedures do not, which is why the focus on the capabilities of each is important in this context.