Create Computer Science.md

Grade 9/Computer Science.md

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+# Computer Science Review Sheet
+
+> ## Exam Layout
+>> |Part|Description|Marks|
+>> |:---|:----------|:----|
+>> |```A```|**True / False**|10|
+>> |```B```|**Multiple Choice**<br>- All java code learnt, selection, loops, methods, Arrays, methods, strings|38|
+>> |```C```|**Short & Long Answers**<br>- Compare and contrast short code, methods, problem solving|20|
+>> |```Total```||68|
+
+## Intro To Programming
+
+> ```Comments```: are used to explain and clarify program ocde for human reader   
+
+> |Operator|Uses|Description|
+> |:-------|:---|:----------|
+> |+|a + b|Addition|
+> |-|a- b|Subtraction|
+> |*|a * b|Multiplication|
+> |/|a / b|Division|
+> |%|a % b|Mod, the Remainder|
+
+> **BEDMAS** rules still apply
+
+> ## Strings
+
+>> **```String:```** means a group of many characters     
+>> **```String Concatenation```**: means that two strings are combined into one using the "r" sign      
+
+> ## Varaibles
+>> Holder for data       
+>> We can use words instead of just a single letter
+>>  - can store more than just numbers     
+>> a place in memory (RAM: random access memory) where it can be stored or referred to      
+>>  - Name, type, value
+
+>> To declare a variable 
+>>  1. Name
+>>  2. Data Type
+
+>> A variable is the name of a reserved memory location     
+>> A varaible name is called an identifier      
+>> Reserved words cannot be used as an identifier    
+
+> ## Java Primitives
+
+> Variables can be created for any of the data types listed       
+> The chart shows examples of how to create a new variable for each primitive    
+
+> |Type|Range|Size|Variable|Declaration|
+> |:---|:----|:---|:-------|:----------|
+> |byte|-128 to 127|8 bits|bits_8|byte bits_8;|
+> |short|-32768 to 32767|16 bits|TALL|short TALL;|
+> |int|-2 billion to 2 billion|32-bits|sum|int sum;|
+> |long|-9 quintillion to 9 quintillion(huge)|64 bits|mile|long mile;|
+> |float|-3.4e<sup>+/-38</sup> to 3.4e<sup>+/-38</sup>|32 bits|pi|float pi;|
+> |double|-1.7e<sup>+/-308</sup> to 1.7<sup>+/-308</sup>|64 bits|stuff|double stuff;|
+> |char|Single (unicode) characters|16 bits|letter|char letter;|
+