The reason functions were invented is to reuse pieces of code. Programs typically need to perform the same operation (such as exponentiation) multiple times, and when you repeat the full code needed to perform the operation every time you need it, your program is going to be a lot longer.
Not only will it be longer, but it will also be more boring to read and more likely to
contain errors. For example, the
power function we defined does not work with negative exponents. If you find out that those are also needed, you’d have to update all ...