(OOPL2) Data Types & Conversion

Leap Year

import java.util.Scanner;

public class LeapYear {
	public static boolean isLeap(int year) {
		if (year % 4 != 0) {
			return false;
		} else if (year % 100 != 0) {
			return true;
		} else if (year % 400 != 0) {
			return false;
		} else {
			return true;
		}
	}

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("Enter the year: ");
		int year = scanner.nextInt();

		System.out.println("Is it a leap year? " + isLeap(year));
	}
}

Implicit & Explicit Conversion

import java.util.Scanner;

public class DataConversion {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);

		System.out.println("Enter the integer: ");
		int integer = scanner.nextInt();

		System.out.println("Enter the double: ");
		double doubler = scanner.nextDouble();

		System.out.println("Enter the character: ");
		char character = scanner.next().charAt(0);

		System.out.println("int to byte: " + (byte)integer);
		System.out.println("char to int: " + (int)character);
		System.out.println("double to byte: " + (byte)doubler);
		System.out.println("double to int: " + (int)doubler);
	}
}

Bitwise Operation (by 2)

import java.util.Scanner;

public class BitwiseOperation {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("Enter the number: ");
		int num = scanner.nextInt();

		System.out.println("The division is " + (num >> 1));
		System.out.println("The multiplication is " + (num << 1));
	}
}

“Observe & Analyze”

public class ObserveAnalyze {
	public static void main(String[] args) {
		int a = 10;
		double b = a;
		System.out.println("1. implicit int to double: " + b);

		double c = 10.5;
		int d = c;
		System.out.println("2. implicit double to int: " + d);

		double e = 10.5;
		int f = (int) e;
		System.out.println("3. explicit double to int:" + f);
	}
}

Four-Function Calculator

import java.util.Scanner;

public class Calculator {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		String choice = null;

		do {
			System.out.println("Enter first number, operator, second number: ");
			String operation = scanner.nextLine();
			String[] operationList = operation.split(" ");
			int firstNum = Integer.parseInt(operationList[0]);
			int secondNum = Integer.parseInt(operationList[2]);

			switch (operationList[1]) {
				case "+":
					System.out.println("Answer is: " + (firstNum + secondNum));
					break;
				case "-":
					System.out.println("Answer is: " + (firstNum - secondNum));
					break;
				case "*":
					System.out.println("Answer is: " + (firstNum * secondNum));
					break;
				case "/":
					System.out.println("Answer is: " + (firstNum / secondNum));
					break;
				default:
					System.out.println("Invalid input.");
			}
			
			System.out.println("Do you want to continue? [y/N]");
			choice = scanner.nextLine();
		} while (choice.equals("y"));
	}
}