Building a Basic Banking System in Java: A Freshers' Challenge

Welcome to our beginner-friendly programming challenge! Today, we’ll guide you through creating a basic banking system using Java. This project will help you understand key concepts like classes, objects, methods, and collections in Java.

Step 1: Create the Account Class

class Account {
    private static int accountCounter = 1000;
    private int accountNumber;
    private String accountHolderName;
    private double balance;

    public Account(String accountHolderName) {
        this.accountNumber = accountCounter++;
        this.accountHolderName = accountHolderName;
        this.balance = 0.0;
    }

    public int getAccountNumber() {
        return accountNumber;
    }

    public String getAccountHolderName() {
        return accountHolderName;
    }

    public double getBalance() {
        return balance;
    }

    public void deposit(double amount) {
        if (amount > 0) {
            balance += amount;
        }
    }

    public void withdraw(double amount) {
        if (amount > 0 && balance >= amount) {
            balance -= amount;
        } else {
            System.out.println("Insufficient funds or invalid amount.");
        }
    }
}

Step 2: Create the Bank Class

import java.util.ArrayList;
import java.util.List;

class Bank {
    private List<Account> accounts = new ArrayList<>();

    public void createAccount(String accountHolderName) {
        Account newAccount = new Account(accountHolderName);
        accounts.add(newAccount);
        System.out.println("Account created. Account Number: " + newAccount.getAccountNumber());
    }

    public Account getAccount(int accountNumber) {
        for (Account account : accounts) {
            if (account.getAccountNumber() == accountNumber) {
                return account;
            }
        }
        return null;
    }

    public void deposit(int accountNumber, double amount) {
        Account account = getAccount(accountNumber);
        if (account != null) {
            account.deposit(amount);
            System.out.println("Deposited " + amount + ". New balance: " + account.getBalance());
        } else {
            System.out.println("Account not found.");
        }
    }

    public void withdraw(int accountNumber, double amount) {
        Account account = getAccount(accountNumber);
        if (account != null) {
            account.withdraw(amount);
            System.out.println("Withdrawn " + amount + ". New balance: " + account.getBalance());
        } else {
            System.out.println("Account not found.");
        }
    }

    public void checkBalance(int accountNumber) {
        Account account = getAccount(accountNumber);
        if (account != null) {
            System.out.println("Current balance: " + account.getBalance());
        } else {
            System.out.println("Account not found.");
        }
    }
}

Step 3: Create the BankingSystem Class

import java.util.Scanner;

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

        while (true) {
            System.out.println("1. Create Account");
            System.out.println("2. Deposit Money");
            System.out.println("3. Withdraw Money");
            System.out.println("4. Check Balance");
            System.out.println("5. Exit");
            System.out.print("Choose an option: ");
            int choice = scanner.nextInt();
            scanner.nextLine();  // Consume newline

            switch (choice) {
                case 1:
                    System.out.print("Enter account holder name: ");
                    String name = scanner.nextLine();
                    bank.createAccount(name);
                    break;
                case 2:
                    System.out.print("Enter account number: ");
                    int depositAccountNumber = scanner.nextInt();
                    System.out.print("Enter amount to deposit: ");
                    double depositAmount = scanner.nextDouble();
                    bank.deposit(depositAccountNumber, depositAmount);
                    break;
                case 3:
                    System.out.print("Enter account number: ");
                    int withdrawAccountNumber = scanner.nextInt();
                    System.out.print("Enter amount to withdraw: ");
                    double withdrawAmount = scanner.nextDouble();
                    bank.withdraw(withdrawAccountNumber, withdrawAmount);
                    break;
                case 4:
                    System.out.print("Enter account number: ");
                    int balanceAccountNumber = scanner.nextInt();
                    bank.checkBalance(balanceAccountNumber);
                    break;
                case 5:
                    System.out.println("Exiting...");
                    scanner.close();
                    return;
                default:
                    System.out.println("Invalid choice. Please try again.");
            }
        }
    }
}