CSE 8A Chapter Notes - Chapter 3.1-3.4: Hard Disk Drive
28 Sep 2016
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Document Summary
Names are useful for people, not computers: a good program is meaningful, understandable, and useful for humans, be specific in naming classes, methods, etc. File - collection of values (bytes) on hard disk (part of computer that stores things) Ram computer"s memory that disappears when power is off. Computers fit more memory into hard disk than memory: data must be read from disk into memory before you can work with it. Naming values allow us to retrieve them later. Wrapper classes wrap around primitive types to have objects to work with: automatically done when needed (boxing and unboxing) Methods put in a value and out comes another: must be defined in a class, class methods. Executed using class name or object of class. Defined using static keyword: object methods. Invoking class methods: classname. methodname(); ie. system. out. println(math. abs(-32)); -> 32. Object methods: objectreference. methodname(), objectreference name of an object variable, can return a new object.
