Week 8 - Linked Lists

                This week the lectures was about the idea of linked lists and it uses. The idea of linked lists are quite literal in which we can imagine an arrow. It consists of a head and tail in which the tail represents the last list created and or source, compared to the head in which it points to the next potential list in a series of list. This series is called a linked list.

                Linked lists is used to provide an organized way to provide a logical list of variable or collections, meaningful to the programmer. For example consider the addition or subtraction of a polynomial, one might find it useful to separate the terms through linked lists and then use the linked list structure to manipulate the terms to perform the mathematical arithmetic.

                Personally, I don’t find linked lists particularly useful for organizing a series of data. I find using binary trees to be easier and more efficient compared to linked lists. So it is highly unlikely that I will make use of linked lists when programming unless it is absolutely require for an assignment and or problem explicitly calls for the need to implement linked lists.

                

Week 7 - Recursion

Well if I had known earlier that I had to talk about recursion this week, I would have not gone into much detail as I have in week 4 when recursion was being taught. Therefore, this entry in the slog will be quite similar to that of week 4.

                So to the question of what recursion is. Recursion is simply put, a function where it attempts to call upon itself repeatedly to get a final value or solve a problem. This is a powerful and unique technique where by the programmer does not need to write excessive code to bring about a solution to a problem where it would seem it would have numerous outcomes and or iterations as such code will have to be written iteratively. Writing code iteratively to solve a lengthy problem with seemingly unknown number of iterations can be both tedious, difficult, impossible and or potentially inefficient. However, it is not say it is the best solution to everything. There are times where writing iterative code is simply easier to read and write due to not having to trace it through multiple layers of code as it calls itself repeatedly.

                As a rule of thumb, if one knows precisely the number of iterations the code would require to fulfill its purpose, one would write code iteratively. Whereas if the code can have multiple iterations that the programmer cannot foresee depending on the parameters given in a function, one would use a recursive function so that the computer would figure the outcome by itself.

                An example would be the code written to draw a Sierpinski’s Triangle whereby 2 integers will be provided, the number of triangles as well as the number of dots. As one can see, the code can be written iteratively but will be both tedious and long. However, a recursive function exists whereby it not only shortens the code, it allows other programmers to understand the function of the code to draw the triangle depending on whatever the user inputted.

                As for my person opinion on recursive functions, they are quite useful albeit painful to analyze when it requires multiple iterations as I easily can get lost in the code. And the fact that it is easy make a single mistake thereby get a wrong answer at the end. Also my opinion as to when recursive functions should be used is explained above. (Use recursive if one does not know the number of iterations the code must go through to produce a useful output and or purpose. Otherwise write and use iterative code as it is often simpler to analyze and understand.)