(OOPL4) Constructors & Static Members

Student Class Modified

import java.util.Scanner;

class Student {
	String name;
	int[] marks = new int[5];
	int total, average;

	public Student() {
		this.name = "";
		this.total = this.average = 0;
	}

	public Student(String name, int total, int average) {
		this.name = name;
		this.total = total;
		this.average = average;
	}

	void assign() {
		Scanner scanner = new Scanner(System.in);

		System.out.println("Enter student name: ");
		this.name = scanner.nextLine();
		System.out.println("Enter marks in 5 subjects: ");
		for (int i = 0; i < 5; i++) {
			this.marks[i] = scanner.nextInt();
		}
	}

	void compute() {
		this.total = 0;
		for (int i = 0; i < this.marks.length; i++) {
			this.total += this.marks[i];
		}
		this.average = this.total / this.marks.length;

		System.out.println("Total and average marks computed.");
	}

	void display() {
		System.out.println("Name: " + this.name);
		System.out.println("Total Marks: " + this.total);
		System.out.println("Average Marks: " + this.average);
	}
}

public class StudentInput {
	public static void main(String[] args) {
		System.out.println("--- MANUAL ASSIGNMENT ---");
		Student student = new Student();
		student.assign();
		student.compute();
		student.display();

		System.out.println("--- DEFAULT CONSTRUCTOR ---");
		Student studentConst = new Student();
		studentConst.display();

		System.out.println("--- PARAMETERIZED CONSTRUCTOR ---");
		Student studentParam = new Student("Butternaan", 489, 92);
		studentParam.display();
	}
}

Employee Class Modified

import java.util.Scanner;

class Employee {
	String name;
	String id;
	double basic = 0;
	double da = 0;
	double it = 0;
	double grossSalary = 0;
	double netSalary = 0;

	public Employee() {
		this.name = "";
		this.id = "None";
		this.basic = this.da = 0;
	}

	public Employee(String name, String id, double basic) {
		this.name = name;
		this.id = id;
		this.basic = basic;
	}

	void read() {
		Scanner scanner = new Scanner(System.in);

		System.out.println("Enter employee name: ");
		this.name = scanner.nextLine();
		System.out.println("Enter employee ID: ");
		this.id = scanner.nextLine();

		System.out.println("Enter basic salary: ");
		this.basic = scanner.nextInt();
	}

	void compute() {
		this.da = 0.52 * this.basic;
		this.grossSalary = this.basic + this.da;
		this.it = 0.3 * this.grossSalary;
		this.netSalary = this.grossSalary + this.it;

		System.out.println("Gross Salary, Net Salary and IT computed.");
	}

	void display() {
		System.out.println("Name: " + this.name);
		System.out.println("ID: " + this.id);
		System.out.println("DA: Rs. " + this.da);
		System.out.println("IT: Rs. " + this.it);
		System.out.println("Gross Salary: Rs. " + this.grossSalary);
		System.out.println("Net Salary: Rs. " + this.netSalary);
	}
}

public class EmployeeInput {
	public static void main(String[] args) {
		System.out.println("--- MANUAL ASSIGNMENT ---");
		Employee employee = new Employee();
		employee.read();
		employee.compute();
		employee.display();

		System.out.println("--- DEFAULT CONSTRUCTOR ---");
		Employee employeeConst = new Employee();
		employeeConst.display();

		System.out.println("--- PARAMETERIZED CONSTRUCTOR ---");
		Employee employeeParam = new Employee("Butternaan", "EM123456", 234000);
		employeeParam.compute();
		employeeParam.display();
	}
}

Bank Account

import java.util.Scanner;

class BankAccount {
	String name;
	String type;
	long number;
	long balance;
	static float rateOfInterest = 3;

	BankAccount() {
		this.name = "NIL";
		this.type = "NIL";
		this.number = 0;
		this.balance = 0;
	}

	BankAccount(String name, String type, long number, long balance) {
		this.name = name;
		this.type = type;
		this.number = number;
		this.balance = balance;
	}

	void deposit(long amount) {
		this.balance += amount;
	}

	boolean withdraw(long amount) {
		if (balance - amount <= 10000) {
			return false;
		} else {
			balance -= amount;
			return true;
		}
	}

	void display() {
		System.out.println();
		System.out.println("Name: " + this.name);
		System.out.println("Account Type: " + this.type);
		System.out.println("Account Number: " + this.number);
		System.out.println("Account Balance: " + this.balance);
		System.out.println();
	}

	static void rateOfInterest() {
		System.out.println("The current rate of interest is: " + rateOfInterest);
	}
}

public class AccountInput {
	public static void main(String[] args) {
		String name;
		String type;
		long number;
		long balance;
		Scanner scanner = new Scanner(System.in);
		String choice = null;

		System.out.println("Enter account holder name: ");
		name = scanner.nextLine();
		System.out.println("Enter account type (Savings/FD/Joint): ");
		type = scanner.nextLine();
		System.out.println("Enter account number: ");
		number = scanner.nextLong();
		System.out.println("Enter balance amount: ");
		balance = scanner.nextLong();

		BankAccount bankAccount = new BankAccount(name, type, number, balance);

		do {
			System.out.print("--- STACK OPERATIONS ---");
			System.out.print("\n1. Deposit Money");
			System.out.print("\n2. Withdraw Money");
			System.out.print("\n3. Display Account Info");
			System.out.print("\n4. Show Rate of Interest.");
			System.out.print("\n\nYour input: ");
			int input = scanner.nextInt();

			switch (input) {
				case 1:
					System.out.println("Enter the amount to deposit: ");
					bankAccount.deposit(scanner.nextLong());
					bankAccount.display();
					break;
				case 2:
					System.out.println("Enter the amount to withdraw: ");
					if (!bankAccount.withdraw(scanner.nextLong())) {
						System.out.println("Amount exceeds minimum balance!");
					} else {
						bankAccount.display();
					}
					break;
				case 3:
					bankAccount.display();
					break;
				case 4:
					BankAccount.rateOfInterest();
				default:
					System.out.println("Invalid input.");
			}

			System.out.println("Do you want to continue? [y/N]");
			choice = scanner.next();
		} while (choice.equals("y"));

		scanner.close();
	}
}

Counter

class Counter {
	static int count = 0;

	Counter() {
		System.out.println("Counter object created.");
		count++;
	}

	static int showCount() {
		return count;
	}
}

public class CounterInput {
	public static void main(String[] args) {
		Counter counter1 = new Counter();
		Counter counter2 = new Counter();
		Counter counter3 = new Counter();
		Counter counter4 = new Counter();
		System.out.println("The number of objects is: " + Counter.showCount());
	}
}