How can you test individual functions without running the entire program?

Testing individual functions separately from the main program is a crucial practice in programming, often referred to as unit testing. This method allows developers to isolate and evaluate specific functionalities without executing the entire codebase, thus making it easier to identify and fix bugs.

By calling them separately from the main code, you can focus on one function at a time, verifying that its output is as expected given a particular input. This targeted approach helps ensure that each component behaves correctly before integrating it into the full program. Furthermore, this strategy supports debugging and improves the efficiency of development since you can quickly validate changes to individual functions without having to test the complete program repeatedly.

Other strategies, such as compiling code separately or running them as separate programs, may not offer the same level of granularity. Using print statements throughout the code, while helpful for debugging, does not effectively test function outputs. It can lead to an incomplete understanding of how functions behave, since print statements don't validate functionality automatically and can clutter the output, making debugging more challenging.