From da449139de216a2eea223cfb06cd4c27f1bfeac3 Mon Sep 17 00:00:00 2001 From: sgoudham Date: Fri, 15 Jan 2021 21:27:59 +0000 Subject: [PATCH] Guide --- Personal/src/Main.java | 201 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 201 insertions(+) create mode 100644 Personal/src/Main.java diff --git a/Personal/src/Main.java b/Personal/src/Main.java new file mode 100644 index 0000000..e317576 --- /dev/null +++ b/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, [] 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 names = new ArrayList<>(); + + // TODO: HashMap Declaration + HashMap jediKnights = new HashMap<>(); + + } + + static void method1(int i) { + i = 20; + } +}