Flowcharts

In Computer Science class this week, we learned about flowcharts.

What is a Flowchart?

A flowchart is simply a more visual way of representing an algorithm. The flowchart is a diagram that illustrates the steps required to solve a problem.

Drawing Flowcharts

Drawing and understanding a flowchart requires some prior knowledge, but it’s very simple to learn. First off, the direction of a flowchart goes from left to right and top to bottom. The lines of the flow must also have arrows denoting their direction. Start and end use elliptical shapes, input/output shapes use parallelograms (that are not rectangles or rhombuses), calculations use rectangles, and the symbol used for decisions is a rhombus.

Flowchart Techniques

Techinique might be a misleading word; these are some commands that are a bit more complex to use when writing an algorithm/flowchart, but they’re not that hard to learn and give you the potential to write so many more different algorithms.

The most basic one is IF. In the picture below, true means that the if statement is fulfilled, while false means that it wasn’t. If false, then the statement directly ends. By using if, you can give different steps for different circumstances, which is obviously extremely handy.

Next is IF ELSE. IF ELSE is similar to IF, but now, if the validity of the statement is false (body of else), then the program will output another statement instead of directly ending.

IF ELSE IF statements build on upon IF ELSE statements (as the name implies). However, when the condition is false (“else”) now, the “false” flow leads to another IF statement. Once again, this increases the possible things you can do with algorithms, as you can now take a holistic approach and divide circumstances even more efficiently than before.

Nested IF statements are practically the same thing as IF ELSE IF statements, but reversed: now, the statement leads to another IF statement if is true, not if its false. In some cases, this is a bit more conventional and easier to understand than IF ELSE IF statements.

Another neat command that can be used is the LOOP statement. As the name implies, a loop statement can let you do a step or multiple steps repeatedly until a certain condition is required. There are two main types of loop statements: WHILE-loops and DO-WHILE-loops. In WHILE-loops, the “true” arrow is vertically straight, and the body needing looping is carried out while looping back to the test expression. In DO-WHILE-loops, the “true” arrow loops back to the test expression, and the body needing looping is carried out once done looping back. The difference is pretty difficult to explain with words, so I provided the two pictures below to show the difference between the two types of loop statements.

Activities

Of course, the best way to learn something is by actually doing it. So, we did some flowchart activities during class. We started with the activity on the left. Mr. Pete gave us two tasks. The first one was to create a flowchart for the product of two numbers. This one overall was pretty straightforward. The second one was to create a flowchart for recognizing if a number is even or odd. These weren’t very difficult tasks, but they were very useful in me solidifying my understanding of flowcharts.

Typing Test

We also had a typing test this week. Mr. Pete really upped the ante by raising the WPM requirement from 20 WPM to 25 WPM. Obviously, typing is an essential skill if you want to work with computers because practically all computer science-related things require typing. If you type fast, your work efficiency is much higher.

Basically…

We learned a lot about flowcharts this week, which was really helpful. Although a bit of a hassle to draw, flowcharts are great because they are intuitive and easy to understand. By designing a flowchart, I strengthened my understanding of programming and algorithms. Obviously, this is very important because of how omniscient and essential programming is in today’s society. I also improved my overall logical thinking, which is helpful for basically everything.