Assignment1.java

import java.util.InputMismatchException;
import java.util.Scanner;
import java.util.Arrays;

class Account {
    private int accountNumber;
    private String accountHolderName;
    private double balance;
    private String email;
    private String phoneNumber;

    public Account(int accountNumber, String accountHolderName, double initialDeposit, String email, String phoneNumber) {
        this.accountNumber = accountNumber;
        this.accountHolderName = accountHolderName;
        this.balance = initialDeposit;
        this.email = email;
        this.phoneNumber = phoneNumber;
    }

    public int getAccountNumber() {
        return accountNumber;
    }

    public boolean deposit(double amount) {
        if (amount <= 0) {
            System.out.println("Error: Deposit amount must be positive.");
            return false;
        }
        this.balance += amount;
        System.out.println("Deposit successful. New balance: " + this.balance);
        return true;
    }

    public boolean withdraw(double amount) {
        if (amount <= 0) {
            System.out.println("Error: Withdrawal amount must be positive.");
            return false;
        }
        if (this.balance < amount) {
            System.out.println("Error: Insufficient balance.");
            return false;
        }
        this.balance -= amount;
        System.out.println("Withdrawal successful. New balance: " + this.balance);
        return true;
    }

    public void displayAccountDetails() {
        System.out.println("\n--- Account Details ---");
        System.out.println("Account Number: " + accountNumber);
        System.out.println("Holder Name: " + accountHolderName);
        System.out.println("Balance: " + balance);
        System.out.println("Email: " + email);
        System.out.println("Phone: " + phoneNumber);
    }

    public void updateContactDetails(String email, String phoneNumber) {
        this.email = email;
        this.phoneNumber = phoneNumber;
        System.out.println("Contact details updated successfully.");
    }
}

public class Main {
    private Account[] accounts;
    private int accountCount;
    private Scanner scanner;
    private static final int MAX_ACCOUNTS = 50;
    private static int nextAccountNumber = 1001;

    public Main() {
        accounts = new Account[MAX_ACCOUNTS];
        accountCount = 0;
        scanner = new Scanner(System.in);
    }

    private Account findAccount(int accountNumber) {
        for (int i = 0; i < accountCount; i++) {
            if (accounts[i].getAccountNumber() == accountNumber) {
                return accounts[i];
            }
        }
        return null;
    }

    private int getIntInput(String prompt) throws InputMismatchException {
        System.out.print(prompt);
        return scanner.nextInt();
    }

    private double getDoubleInput(String prompt) throws InputMismatchException {
        System.out.print(prompt);
        return scanner.nextDouble();
    }

    public void createAccount() {
        if (accountCount >= MAX_ACCOUNTS) {
            System.out.println("Error: Maximum account limit reached.");
            return;
        }

        try {
            System.out.print("Enter account holder name: ");
            String name = scanner.nextLine();

            double initialDeposit = getDoubleInput("Enter initial deposit amount: ");
            scanner.nextLine();

            System.out.print("Enter email address: ");
            String email = scanner.nextLine();
            System.out.print("Enter phone number: ");
            String phone = scanner.nextLine();

            if (initialDeposit < 0) {
                System.out.println("Error: Initial deposit cannot be negative.");
                return;
            }

            Account newAccount = new Account(nextAccountNumber, name, initialDeposit, email, phone);
            accounts[accountCount++] = newAccount;
            System.out.println("Account created successfully with Account Number: " + nextAccountNumber);
            nextAccountNumber++;
        } catch (InputMismatchException e) {
            System.out.println("Error: Invalid input. Amount must be a number.");
            scanner.nextLine();
        }
    }

    public void performDeposit() {
        try {
            int accountNumber = getIntInput("Enter account number: ");
            double amount = getDoubleInput("Enter amount to deposit: ");
            scanner.nextLine();

            Account account = findAccount(accountNumber);
            if (account != null) {
                account.deposit(amount);
            } else {
                System.out.println("Error: Account not found.");
            }
        } catch (InputMismatchException e) {
            System.out.println("Error: Invalid input. Account number and amount must be numbers.");
            scanner.nextLine();
        }
    }

    public void performWithdrawal() {
        try {
            int accountNumber = getIntInput("Enter account number: ");
            double amount = getDoubleInput("Enter amount to withdraw: ");
            scanner.nextLine();

            Account account = findAccount(accountNumber);
            if (account != null) {
                account.withdraw(amount);
            } else {
                System.out.println("Error: Account not found.");
            }
        } catch (InputMismatchException e) {
            System.out.println("Error: Invalid input. Account number and amount must be numbers.");
            scanner.nextLine();
        }
    }

    public void showAccountDetails() {
        try {
            int accountNumber = getIntInput("Enter account number: ");
            scanner.nextLine();

            Account account = findAccount(accountNumber);
            if (account != null) {
                account.displayAccountDetails();
            } else {
                System.out.println("Error: Account not found.");
            }
        } catch (InputMismatchException e) {
            System.out.println("Error: Invalid input. Account number must be an integer.");
            scanner.nextLine();
        }
    }

    public void updateContact() {
        try {
            int accountNumber = getIntInput("Enter account number to update: ");
            scanner.nextLine();

            Account account = findAccount(accountNumber);
            if (account != null) {
                System.out.print("Enter new email address: ");
                String newEmail = scanner.nextLine();
                System.out.print("Enter new phone number: ");
                String newPhone = scanner.nextLine();
                account.updateContactDetails(newEmail, newPhone);
            } else {
                System.out.println("Error: Account not found.");
            }
        } catch (InputMismatchException e) {
            System.out.println("Error: Invalid input. Account number must be an integer.");
            scanner.nextLine();
        }
    }

    public void mainMenu() {
        int choice = 0;
        do {
            System.out.println("\nWelcome to the Banking Application!");
            System.out.println("1. Create a new account");
            System.out.println("2. Deposit money");
            System.out.println("3. Withdraw money");
            System.out.println("4. View account details");
            System.out.println("5. Update contact details");
            System.out.println("6. Exit");
            System.out.print("Enter your choice: ");

            try {
                choice = scanner.nextInt();
                scanner.nextLine();

                switch (choice) {
                    case 1: createAccount(); break;
                    case 2: performDeposit(); break;
                    case 3: performWithdrawal(); break;
                    case 4: showAccountDetails(); break;
                    case 5: updateContact(); break;
                    case 6:
                        System.out.println("Thank you for using the Banking Application. Goodbye!");
                        break;
                    default:
                        System.out.println("Invalid choice. Please enter a number from 1 to 6.");
                }
            } catch (InputMismatchException e) {
                System.out.println("Error: Invalid input. Please enter a valid menu number.");
                choice = 0;
                scanner.nextLine();
            }
        } while (choice != 6);
    }

    public static void main(String[] args) {
        Main app = new Main();
        try {
            app.mainMenu();
        } finally {
            if (app.scanner != null) {
                app.scanner.close();
            }
        }
    }
}