Computer Science and Checkers

                For my final blog post I am going to talk about computer science.  To help me explain such a broad topic, I am going to use a program I wrote a few months ago that simulates a game of checkers when you run it and, due to a limited amount of space, I can only briefly talk about the concepts behind this program. Since Computer Science and the program I'm using as an example are both very complex topics, I'm going to primarily focus on the way a computer thinks when it compiles code. Before I can go on to explain checkers, I would like to talk about how computers think and function very briefly. A computer can't look at a situation and assess it like we can as humans.  A computer can only recognize two things: whether a condition is true or false. To best show what this means, you can look at binary. Our number system is called decimal.  It has ten digits and is easy for us to understand because we can count to 10 on our fingers and it's a fairly simple system. Binary is different in the sense that it only has two digits--0 and 1, 1 being true and 0 being false. At the end of this post I've linked a video that explains how to convert from decimal to binary for those who are interested in the topic.

                 Since a computer can only recognize things as true or false, you  have to keep this in mind when you construct the game board. To do this, I used something called a two-dimensional array or a matrix. A matrix is like a grid where it has two values (an x and a y) and it uses those two values to find the place in the matrix you're looking for, then it returns that information.  I've posted a picture of the matrix bellow.

                             

      As you can see, there are four different values on the board: an X which represents the spaces you can't "jump" your pieces to, an empty space which represents the empty places on the board, a capital O which represents one player's pieces, and a lowercase o which represents the other player's pieces. Now that I have a board created, the next step I had to take in writing my program was taking this matrix and making a visual representation of it as a game board. To do this, I used text and something called a loop. A loop is a type of function that will repeat itself until its condition is false.

     The image above is a picture of the two loops I used. While it may look complicated at first glance, when you break it down it is relatively easy to understand.  First, I needed to create two integer values, which are values that can only be whole numbers.  I named them count and countTwo. Then to make it easy to understand the grid and select pieces I include the line System.out.println("      0.   1.   2.   3.   4.   .5   .6   7.").  The function of this is that it prints out whatever is inside of the quotation marks so, in this case it is  0.-7.. The next line says while(count<8). This line creates the loop that I mentioned earlier.  What it is saying is that it is going to re-run the lines of code inside of its curly brackets until count is no longer less than 8, or in other words, until the condition is false. The next line is another print line; however, the only difference between this one and the previous one is that it says print instead of println. What this difference does is that the println automatically creates a new line after it prints out its statement and the one that only says print does not. The next line is another loop that will run until countTwo is no longer less than 8. Then inside of that loop is another print statement that prints (board[count][countTwo ] + " | "). This print statement is going to grab the value at board[count][countTwo] which is like a co-ordinate plane at the point (x,y). It then separates that with a line from the next value it prints. The second loop also contains the line countTwo++ which adds 1 to countTwo.  The first time it runs, it will grab the value from board[0][0] which is X. Then  the second loop will run again printing out the value of board[0][1] which is an o. It repeats this process 8 times.  Then because countTwo is no longer less than 8, it leaves the second loop. The next couple of lines are count++ and countTwo=0.  Count++ adds one on to count, countTwo = 0 resets countTwo so that it no longer equals 8 but 0 again. Then the first loop repeats. Since countTwo was reset to equal 0, the second loop also repeats again, going through another 8 times.  This time it is printing out the values at board[1][CountTwo] instead of board[0][countTwo]. The entire process repeats until count equals 8 and it prints out the entire board, which ends up looking like the following picture. 

 

     Unfortunately due to a lack of space I could only briefly describe to concepts of this program. Other parts of this program include: selecting a piece to move, returning move options for the selected piece, identifying when a player can jump another piece, identifying the possibility of multiple jumps, and also implementing the king piece.

https://www.youtube.com/watch?v=Q2UgMYwWiO4 - David Williams: Base 10 to Base 2 (Decimal to Binary) Conversion