Re-usable code (cont'd)

We don't need to write the square root code ourselves. 

All we need to do is to re-use the code written by the Alice team by calling the function.

If we need to compute the square roots of ten different numbers at ten different times during the execution of the program:

It isn't necessary to duplicate all of the code necessary to compute the square root of a number each time a square root value is needed.