Guide

Personal/src/Main.java

@@ -0,0 +1,201 @@
+import java.util.ArrayList;
+import java.util.HashMap;
+
+public class Main {
+    public static void main(String[] args) {
+        int x = 18;
+        // method1(x); System.out.println(x);
+
+
+        for (int i = 0; i < 10; i++) {
+            System.out.println(i + " Hello World!");
+        }
+
+        // TODO: While Loop
+        // Output: Same As For Loop Shown Previously
+        int p = 0;
+        while (p < 10) {
+            System.out.println(p + " Hello World!");
+            p++;
+        }
+
+        // TODO: Do While Loop
+        /* Note: Condition is checked at the end
+        *        so the loop will ALWAYS execute
+        *        at least once, even if the condition
+        *        is false.
+        * Output: Goudham
+        */
+        int j = 0;
+        do {
+            System.out.println("Goudham");
+        } while (j != 0);
+
+//        // TODO: If Else Statement
+//        // Operator Used: Less Than (<)
+//        // Output: You Are Rich!
+//        double balance = 500.00;
+//        if (balance < 500.00) {
+//            System.out.println("You Are Broke");
+//        } else {
+//            System.out.println("You Are Rich!");
+//        }
+
+        // TODO: If else if else if... Statement
+        // Operator(s) Used: Logical AND (&&), Logical NOT (!),
+        //                   Greater Than (>), Greater Than Or Equal To (>=),
+        //                   Less Than (<),
+        // Output: You Are Rich and not in Debt
+        double balance = 100.00;
+        boolean debt = false;
+
+        if (balance < 100.00 && debt) {
+            System.out.println("You are Broke and in Debt");
+        } else if (balance >= 100.00 && debt) {
+            System.out.println("You are Rich but in Debt");
+        } else if (balance < 100.00 && !debt) {
+            System.out.println("You are Broke and not in Debt");
+        } else if (balance >= 100.00 && !debt) {
+            System.out.println("You are Rich and not in Debt");
+        }
+
+        // TODO: Switch Case Statement
+        /* Note: There is no major difference between this and
+                 if else if else if... The switch statement
+                 improves readability and clarity.
+         */
+        // Output: Wednesday
+        int day = 3;
+        switch (day) {
+            case 1:
+                System.out.println("Monday");
+                break;
+            case 2:
+                System.out.println("Tuesday");
+                break;
+            case 3:
+                System.out.println("Wednesday");
+                break;
+            case 4:
+                System.out.println("Thursday");
+                break;
+            case 5:
+                System.out.println("Friday");
+                break;
+            case 6:
+                System.out.println("Saturday");
+                break;
+            case 7:
+                System.out.println("Sunday");
+                break;
+            default:
+                System.out.println("Day Not Specified");
+        }
+
+
+        // TODO: Another If Statement
+        // Operator Used: Logical NOT (!)
+        // Output: You Are Broke
+        boolean rich = false;
+        if (!rich) {
+            System.out.println("You Are Broke");
+        }
+
+        // TODO: Common String Methods
+        String helloWorld = "Hello World!";
+
+        // TODO .toUpperCase()
+        // Converts the entire string into uppercase format
+        // Return Type: String
+        // Output: HELLO WORLD!
+        System.out.println(helloWorld.toUpperCase());
+
+        // TODO: .toLowerCase()
+        // Converts the entire string into lowercase format
+        // Return Type: String
+        // Output: hello world!
+        System.out.println(helloWorld.toLowerCase());
+
+        // TODO: .isEmpty()
+        // Checks to see if the string is empty or not
+        // Return Type: boolean
+        // Output: false
+        System.out.println(helloWorld.isEmpty());
+
+        // TODO .length()
+        // Returns the length of the string given
+        // Return Type: int
+        // Output: 12
+        System.out.println(helloWorld.length());
+
+        // TODO .concat()
+        // Appends a string onto the end of another string
+        // Return Type: String
+        // Output: Hello World!World
+        System.out.println(helloWorld.concat("World"));
+
+        // TODO .contains()
+        // Checks to see a string is present within another string
+        // Return Type: boolean
+        // Output: true
+        System.out.println(helloWorld.contains("Hello"));
+
+        // TODO .equals()
+        // Checks if 2 strings are equal
+        // Return Type: boolean
+        // Output: true
+        System.out.println(helloWorld.equals("Hello World!"));
+
+        // TODO .trim()
+        // Erases whitespace from both sides of the string
+        // Return Type: String
+        // Output: Hello World!
+        System.out.println(helloWorld.trim());
+
+        // TODO: Array Declaration
+        // Note: Both ways are valid HOWEVER, <type>[] <name> is the preferred/conventional method
+        String[] jedi = new String[5];;
+        String sith[] = new String[5];;
+
+        // TODO: Array Declaration with Literal Syntax
+        String[] lecturers = new String[] {"Matthew", "Derek", "Waqar"};
+        String[] lecturers1 = {"Matthew", "Derek", "Waqar"};
+
+        // TODO: Array Common Operations
+        // String[] jedi = new String[] {"Goudham", "Luke", "Ahsoka"};
+
+        // TODO: Change Element
+        // Note: We need to specify the index of the value that we want to change
+        // Result: First Element is now "Matthew"
+        jedi[0] = "Matthew";
+
+        // TODO: Find Array Length
+        // Result: Returns the number of elements in an array
+        int lengthOfJediArray = jedi.length;
+
+        // TODO: Loop Through Array
+        for (int i = 0; i < jedi.length; i++) {
+            String currentJedi = jedi[i];
+            // ...
+        }
+
+
+        // TODO: Displaying Arrays
+        System.out.println(jedi);
+
+
+
+
+
+        // TODO: ArrayList Declaration
+        ArrayList<String> names = new ArrayList<>();
+
+        // TODO: HashMap Declaration
+        HashMap<String, String> jediKnights = new HashMap<>();
+
+    }
+
+    static void method1(int i) {
+        i = 20;
+    }
+}