A java cheatsheet

content/blog/2022-02-26-ferris-sweep.md

@@ -10,5 +10,6 @@ extra:
   auto_center_images: true
 ---
 
-After getting myself in to the world of customized mechanical keyboards with my [vortex core](/blog/2020-11-6-vortex-core) two years ago, I have proceeded to dive further into the hobby by [modifying keyboard firmware](/blog/qmk-vortex-core) and eventually building myself a TG4X for daily use.
+After getting myself in to the world of customized mechanical keyboards with my [vortex core](/blog/2020-11-6-vortex-core) two years ago, I have proceeded to dive further into the hobby by [modifying keyboard firmware](/blog/qmk-vortex-core) and eventually building myself a TG4X for daily use. The TG4X has been a great keyboard, and my muscle memory has completely switched over to the quirks of using a 40% layout in daily use. 
 
+<!-- Of course, I shall not settle for a whole 45 keys on my keyboard, **we must go smaller!**. Thus, I have built my very own customised [ferris sweep](#) -->

content/blog/2022-03-15-Java-cheatsheet.md

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+---
+layout: page
+title: "A Java development cheatsheet for my classmates" 
+description: "PROG10082: Reference Material"
+date:   2022-03-15
+tags: reference
+draft: false
+extra:
+  uses_katex: false
+  auto_center_images: true
+---
+
+This document is written for my PROG10082 classmates as a quick reference for some Java concepts that were skipped over in the course. This document may be updated as needed.
+
+## VSCode Tips
+
+*Remember*, you can open [intelisense](https://code.visualstudio.com/docs/editor/intellisense) by pressing <kbd>Ctrl</kbd> + <kbd>Space</kbd>. This is a super handy tool for auto-complete in your code no matter the language you are working in.
+
+Typing the following then opening intelisense will give you some shorthand options for quickly typing common code. Just select the option you want with arrow keys, and press <kbd>Enter</kbd> to apply it.
+
+| Shortcut | Description                                 |
+|----------|---------------------------------------------|
+| `syso`   | Automatically print `System.out.println();` |
+| `syserr` | Automatically print `System.err.println();` |
+
+## Upper and lowercase types
+
+Many types you encounter in Java have an uppercase and lowercase variant, for example `int` and `Integer`. The difference is important. Here are the avalible uppercase variants of common types:
+
+| Standard type | Uppercase type |
+|---------------|----------------|
+| `short`       | `Short`        |
+| `char`        | `Character`    |
+| `byte`        | `Byte`         |
+| `int`         | `Integer`      |
+| `double`      | `Double`       |
+| `float`       | `Float`        |
+| `long`        | `Long`         |
+
+### Null and optional values
+
+One uses of the uppercase variant of a type is to allow `null` values. In most languages, `null` means "Nothing". In Java, you can use `null` to indicate that a variable is not yet assigned a value. This can be checked with the `==` operator.
+
+An example usage of this could be the following:
+
+```java
+// We want to ask for a number of records to read
+Scanner input = new Scanner(System.in);
+int recordCount = input.nextInt();
+
+// Create a value to store the highest record in
+// I have made this `null` so we can know if we didnt get a value
+Integer highestRecord = null;
+
+// Read the records
+for (int i = 0; i < recordCount; i++) {
+    // Read a value
+    int record = input.nextInt();
+
+    // If the value is higher than the current highest record
+    // or the highest record is `null`, update the highest record
+    if (highestRecord == null || record > highestRecord) {
+        highestRecord = record;
+    }
+}
+
+// We now have the highest record
+if (highestRecord != null) {
+    System.out.println("The highest record is " + highestRecord);
+} else {
+    System.out.println("No records were entered");
+}
+```
+
+### Pass-by-reference
+
+Another use of uppercase types is pass-by-reference. 
+
+```java
+// This is a function that will try to add `1` to a value
+void addOne(int value) {
+    value = value + 1;
+}
+
+void main(String ...args) {
+    // We can make a value
+    int myNumber = 1;
+
+    // And pass it to a function. You would expect this to work
+    addOne(myNumber);
+
+    // But at this point, `myNumber` is still `1`
+}
+```
+
+Now, we can switch to using uppercase types to make the function edit the value.
+
+```java
+// This is a function that will try to add `1` to a value
+void addOne(Integer value) {
+    value = value + 1;
+}
+
+void main(String ...args) {
+    // We can make a value
+    Integer myNumber = 1;
+
+    // And pass it to a function. This will work, since we have an upprcase type
+    addOne(myNumber);
+
+    // At this point, `myNumber` is now `2`
+}
+```