content: import java.util.HashMap;
  import java.util.Scanner;
  
  class Account {
      private String accountNumber;
      private double balance;
  
      public Account(String accountNumber, double initialBalance) {
          this.accountNumber = accountNumber;
          this.balance = initialBalance;
      }
  
      public String getAccountNumber() {
          return accountNumber;
      }
  
      public double getBalance() {
          return balance;
      }
  
      public void deposit(double amount) {
          balance += amount;
      }
  
      public boolean withdraw(double amount) {
          if (balance >= amount) {
              balance -= amount;
              return true;
          }
          return false;
      }
  
      @Override
      public String toString() {
          return "Account Number: " + accountNumber + ", Balance: " + balance;
      }
  }
  
  public class BankingSystem {
      private HashMap<String, Account> accounts;
  
      public BankingSystem() {
          accounts = new HashMap<>();
      }
  
      public void createAccount(String accountNumber, double initialBalance) {
          accounts.put(accountNumber, new Account(accountNumber, initialBalance));
      }
  
      public void deposit(String accountNumber, double amount) {
          Account account = accounts.get(accountNumber);
          if (account != null) {
              account.deposit(amount);
          } else {
              System.out.println("Account not found.");
          }
      }
  
      public void withdraw(String accountNumber, double amount) {
          Account account = accounts.get(accountNumber);
          if (account != null) {
              if (!account.withdraw(amount)) {
                  System.out.println("Insufficient balance.");
              }
          } else {
              System.out.println("Account not found.");
          }
      }
  
      public void showAccounts() {
          for (Account account : accounts.values()) {
              System.out.println(account);
          }
      }
  
      public static void main(String[] args) {
          BankingSystem bank = new BankingSystem();
          Scanner scanner = new Scanner(System.in);
          int choice;
  
          do {
              System.out.println("1. Create Account\n2. Deposit\n3. Withdraw\n4. Show Accounts\n5. Exit\nChoose an option: ");
              choice = scanner.nextInt();
              scanner.nextLine(); // consume newline
              switch (choice) {
                  case 1:
                      System.out.print("Enter account number: ");
                      String accountNumber = scanner.nextLine();
                      System.out.print("Enter initial balance: ");
                      double initialBalance = scanner.nextDouble();
                      bank.createAccount(accountNumber, initialBalance);
                      break;
                  case 2:
                      System.out.print("Enter account number: ");
                      String accNumber = scanner.nextLine();
                      System.out.print("Enter amount to deposit: ");
                      double depositAmount = scanner.nextDouble();
                      bank.deposit(accNumber, depositAmount);
                      break;
                  case 3:
                      System.out.print("Enter account number: ");
                      String accNum = scanner.nextLine();
                      System.out.print("Enter amount to withdraw: ");
                      double withdrawAmount = scanner.nextDouble();
                      bank.withdraw(accNum, withdrawAmount);
                      break;
                  case 4:
                      bank.showAccounts();
                      break;
              }
          } while (choice != 5);
  
          scanner.close();
      }
  }
  