... konulu sunumlar: "Bilgisayarlar kodu nasıl işler? Top-down yaklaşım Modüler yaklaşım."— Sunum transkripti:
Bilgisayarlar kodu nasıl işler? Top-down yaklaşım Modüler yaklaşım
Top down yaklaşım In this scenario, when the code is run the computer starts reading at the top and continues down, going through each line of code until it reaches the end. Old method Fast and easy when code was small and not very complex As the code is processed, it is all loaded into memory
Top down yaklaşım So, the more programs you run, the greater the demands on the system in terms of memory and processor
Top down yaklaşım Also, the bigger the program you are loading, the longer and longer it will take to load up
Top down yaklaşım One is that you have to write code in such a way that it is hard to properly test it until you have finished it. Testing individual parts becomes a nightmare.
Breaking up Code There are huge advantages to coding in this way. The code is broken up into smaller components, so it is easier to write and you can test it earlier and more often. Debugging any code errors is a lot easier because you know what part of the code handles what aspect of the program. You are in a position to reuse certain parts of your code in other projects more easily because they will be self-contained. Building up a big project from smaller, interconnected chunks enables you to build up a project over time and add more features as your skills improve!
Kodun Saklanması (Depolanması) To really make applications usable, you need a way to store the code Storage means that you only have to type or ( more accurately) create the code once, storing it for future access –Paper punch cards –Magnetic tape reels –Magnetic cassettes –Floppy disks (5 1/ 4 inch) –Floppy disks (3 1/ 2 inch) –Hard drives –Networked systems –CDs –DVD –Flash drives –Internet distribution
Data Data stored as binary
Plain text vs. Compiled Plain text –The main advantage to code stored in plain text is that it is easily read, changes can be made to it easily and quickly, and no special tools are required. –No protection! Compiled –You can’t look at the compiled code and get back to the source code that way. Therefore protected. –You need to keep a copy of the source code in case you need to make any subsequent changes to the code.
Sayı Sistemleri Decimal (Onluk sayı sistemi, On tabanlı) –0 1 2 3 4 5 6 7 8 9 –Örnek: 1984 Binary (İkilik sayı sistemi, iki tabanlı) –0 1 –Örnek: 10011 Hexadecimal (Onaltılık sayı sistemi) –0 1 2 3 4 5 6 7 8 9 A B C D E F –Örnek: 1A2
İkilik sayı sisteminde terimler Bit - 0,1 Nybble – 4 bit –Örnek: 1010 Byte – 8 bit –Örnek: 10101010 Halfword – 16 bit –Örnek: 1010101010101010 Word – 32 bit –Örnek: 10101010101010101010101010101010 Doubleword – 64 bit –Örnek: 1010101010101010101010101010101010101010101010101010101010101010
Binary ve Hexadecimal arasında dönüşümler 0x3F7D (3F7D) 16 =(?) 2 3F7D 0010111101111101 10111101111101 (101111) 2 =(?) 16 00101111 2F
Binary ve Hexadecimal arasında dönüşümler
Sayı sistemlerinde matematik işlemleri Başlat – Programlar – Donatılar – Hesap Makinesi
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Bilgisayarda Alfasayısal Bilginin Temsil Edilmesi ASCII (American Standard Code for Information Interchange)ASCII (American Standard Code for Information Interchange) Bilgi Değişimi için Amerikan Standart Kodu