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‎README.md‎

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## Types:
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- Primitive: for storing simple values, like numbers, characters, booleans
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![preview](preview/preview-4.png)
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- Primitive: for storing simple values, like numbers, characters, booleans.
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![preview](preview/preview-4.png)
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- How primitive types are stored in memory.
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}
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```
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## Mortgage Calculator:
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## Mortgage Calculator - v1.0:
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```bash
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public class Main {
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}
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}
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```
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## Switch Statements:
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```bash
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public class Main {
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public static void main(String[] args) {
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String role = "admin";
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switch (role) {
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case "admin":
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System.out.println("You're an admin");
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break;
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case "moderator":
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System.out.println("You're a moderator");
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break;
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default:
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System.out.println("You're a guest");
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}
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if (role == "admin") {
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System.out.println("You're an admin");
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} else if (role == "moderator") {
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System.out.println("You're a moderator");
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} else {
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System.out.println("You're a guest");
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}
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}
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}
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```
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## Exercise: FizzBuzz:
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```bash
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public class Main {
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public static void main(String[] args) {
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Scanner scanner = new Scanner(System.in);
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System.out.print("Number: ");
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int number = scanner.nextInt();
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boolean moduloFive = (number % 5) == 0;
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boolean moduloThree = (number % 3) == 0;
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if (moduloFive && moduloThree) {
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System.out.println("FizzBuzz");
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} else if (moduloFive) {
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System.out.println("Fizz");
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} else if (moduloThree) {
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System.out.println("Buzz");
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} else {
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System.out.println(number);
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}
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}
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}
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```
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## Loops in Java:
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```bash
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public class Main {
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public static void main(String[] args) {
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Scanner scan = new Scanner(System.in);
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/*FOR LOOPS*/
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for (int i = 0; i < 5; i++) {
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System.out.println("Hello, Java!");
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}
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/*WHILE LOOPS: USED WHEN DON'T KNOW HOW MANY TIMES WE NEED TO EXECUTE CODE*/
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int i = 0;
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while (i < 5) {
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System.out.println("Hello, Java!");
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i++;
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}
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String input = "";
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while (!input.equals("quit")) {
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System.out.print("Input: ");
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input = scan.next().toLowerCase(Locale.ROOT);
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System.out.println(input);
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}
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/*DO-WHILE LOOPS: SIMILAR TO WHILE-LOOP BUT IT EXECUTES ATLEAST 1 TIME*/
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do {
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System.out.print("Input: ");
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input = scan.next().toLowerCase(Locale.ROOT);
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System.out.println(input);
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} while (!input.equals("quit"));
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}
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}
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```
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## Break & Continue Keywords:
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```bash
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public class Main {
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public static void main(String[] args) {
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Scanner scan = new Scanner(System.in);
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String input = "";
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while (true) {
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System.out.print("Input: ");
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input = scan.next().toLowerCase(Locale.ROOT);
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if (input.equals("pass")) {
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continue;/*moves control to the beginning of the loop*/
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}
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if (input.equals("quit")) {
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break;/*break out of the loop*/
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}
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System.out.println(input);
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}
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}
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}
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```
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## Mortgage Calculator - v2.0:
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```bash
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public class Main {
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public static void main(String[] args) {
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final byte MONTHS_IN_YEAR = 12;
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final byte PERCENT = 100;
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int principal;
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float annualInterest;
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float monthlyInterest;
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byte years;
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int numberOfPayments;
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Scanner scanner = new Scanner(System.in);
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while (true) {
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System.out.print("Principal ($1K - $1M): ");
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principal = scanner.nextInt();
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if (principal >= 1000 && principal <= 1_000_000) {
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break;
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}
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System.out.println("Enter a value between $1000 and $1,000,000");
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}
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while (true) {
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System.out.print("Annual Interest Rate (1% - 30%): ");
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annualInterest = scanner.nextFloat();
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if (annualInterest >= 1 && annualInterest <= 30) {
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monthlyInterest = annualInterest / PERCENT / MONTHS_IN_YEAR;
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break;
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}
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System.out.println("Enter a value between 1 and 30");
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}
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while (true) {
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System.out.print("Period (1 Years- 30 Years): ");
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years = scanner.nextByte();
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if (years >= 1 && years <= 30) {
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numberOfPayments = years * MONTHS_IN_YEAR;
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break;
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}
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System.out.println("Enter a value between 1 and 30");
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}
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/*calculating mortgage*/
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double mortgage = principal * (monthlyInterest * Math.pow(1 + monthlyInterest, numberOfPayments) / (Math.pow(1 + monthlyInterest, numberOfPayments) - 1));
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System.out.println("Mortgage: " + NumberFormat.getCurrencyInstance().format(mortgage));
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}
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}
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```
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## Creating Methods:
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```bash
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public class Main {
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public static void main(String[] args) {
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String message = greetUser("Avinash", "Kumar");
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System.out.println(message);
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}
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public static String greetUser(String firstName, String lastName){
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return "Hello " + firstName + " " + lastName;
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}
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}
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```
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## Mortgage Calculator - v3.0:
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```bash
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public class Main {
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public static void main(String[] args) {
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int principal = (int) readNumber("Principal ($1K - $1M): ", 1000, 1_000_000);
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float annualInterest = (float) readNumber("Annual Interest Rate (1% - 30%): ", 1, 30);
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byte years = (byte) readNumber("Period (1 Years- 30 Years): ", 1, 30);
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double mortgage = calculateMortgage(principal, annualInterest, years);
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System.out.println("Mortgage: " + NumberFormat.getCurrencyInstance().format(mortgage));
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}
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public static double readNumber(String prompt, double min, double max) {
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Scanner scanner = new Scanner(System.in);
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double value;
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while (true) {
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System.out.print(prompt);
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value = scanner.nextDouble();
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if (value >= min && value <= max) {
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break;
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}
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System.out.println("Enter a value between " + min + " and " + max);
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}
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return value;
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}
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public static double calculateMortgage(int principal, float annualInterest, byte years) {
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final byte MONTHS_IN_YEAR = 12;
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final byte PERCENT = 100;
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float monthlyInterest = annualInterest / PERCENT / MONTHS_IN_YEAR;
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short numberOfPayments = (short) (years * MONTHS_IN_YEAR);
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return principal * (monthlyInterest * Math.pow(1 + monthlyInterest, numberOfPayments) / (Math.pow(1 + monthlyInterest, numberOfPayments) - 1));
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}
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}
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```
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## Mortgage Calculator - Clean Code:
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```bash
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public class Main {
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final static byte MONTHS_IN_YEAR = 12;
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final static byte PERCENT = 100;
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public static void main(String[] args) {
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int principal = (int) readNumber("Principal ($1K - $1M): ", 1000, 1_000_000);
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float annualInterest = (float) readNumber("Annual Interest Rate (1% - 30%): ", 1, 30);
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byte years = (byte) readNumber("Period (1 Years- 30 Years): ", 1, 30);
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printMortgage(principal, annualInterest, years);
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printPaymentSchedule(principal, annualInterest, years);
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}
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private static void printPaymentSchedule(int principal, float annualInterest, byte years) {
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System.out.println();
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System.out.println("PAYMENTS SCHEDULE:");
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System.out.println("------------------");
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for (short month = 1; month <= years * MONTHS_IN_YEAR; month++) {
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double balance = calculateBalance(principal, annualInterest, years, month);
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System.out.println(NumberFormat.getCurrencyInstance().format(balance));
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}
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}
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private static void printMortgage(int principal, float annualInterest, byte years) {
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System.out.println();
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System.out.println("MORTGAGE");
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System.out.println("--------");
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double mortgage = calculateMortgage(principal, annualInterest, years);
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System.out.println("Monthly Payments: " + NumberFormat.getCurrencyInstance().format(mortgage));
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}
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public static double readNumber(String prompt, double min, double max) {
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Scanner scanner = new Scanner(System.in);
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double value;
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while (true) {
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System.out.print(prompt);
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value = scanner.nextDouble();
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if (value >= min && value <= max) {
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break;
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}
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System.out.println("Enter a value between " + min + " and " + max);
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}
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return value;
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}
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public static double calculateBalance(int principal, float annualInterest, byte years, short numberOfPaymentsMade) {
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float monthlyInterest = annualInterest / PERCENT / MONTHS_IN_YEAR;
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short numberOfPayments = (short) (years * MONTHS_IN_YEAR);
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double balance = principal * (Math.pow(1 + monthlyInterest, numberOfPayments) - Math.pow(1 + monthlyInterest, numberOfPaymentsMade)) / (Math.pow(1 + monthlyInterest, numberOfPayments) - 1);
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return balance;
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}
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public static double calculateMortgage(int principal, float annualInterest, byte years) {
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float monthlyInterest = annualInterest / PERCENT / MONTHS_IN_YEAR;
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short numberOfPayments = (short) (years * MONTHS_IN_YEAR);
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return principal * (monthlyInterest * Math.pow(1 + monthlyInterest, numberOfPayments) / (Math.pow(1 + monthlyInterest, numberOfPayments) - 1));
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}
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}
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```
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## Refactoring
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- Changing the structure of the code without changing its behaviour.
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- Keep your methods short
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- Extract repetitive patterns
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- Extract highly related statements
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## Types of Errors
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- Compile - Time Errors
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- Run - Time Errors
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## Running a Java Archive (.jar) in local:
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```bash
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java -jar file-name.jar
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```
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## Thank You!
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![preview](preview/preview-8.png)

‎preview/preview-8.png‎

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