Question

Can you help me rearrange my code by incorporating switch I'm not really sure how to do it and it makes the code look cleaner. Can you help me do it but still give the same output? Also kindly add an in-line comment on what changes and rearrangement you've done so I can understand what's going on.

import java.util.ArrayList;

import java.util.Scanner;

public class Bank {

/**
* Add and read bank information to the user.
* @param arg A string, double and int array containing
* the command line arguments.
* @exception Any exception
* @return an arraylsit of bank customers
*/

// method to display the menu
static void menu() {

System.out.println("\n1. Add a bank customer");

System.out.println("2. Remove a bank customer");

System.out.println("3. Print all bank customers");

System.out.println("4. Quit");

}

// method to add a customer in sorted order of account number into an array

// list. returns true if addition is successful, else false

static boolean addCustomer(ArrayList<BankCustomer> customers,

BankCustomer newCustomer) {

// looping and finding the proper position to add

for (int i = 0; i < customers.size(); i++) {
  
// checking if new customer can be added to index i
  
if (newCustomer.getAcctNumber() < customers.get(i).getAcctNumber()) {

// adding to index i

customers.add(i, newCustomer);

return true; // success

} else if (newCustomer.getAcctNumber() == customers.get(i)

.getAcctNumber()) {

// duplicate found, returning false

return false;

}
  
}

// adding to the end, if still not added

customers.add(newCustomer);

return true; // success

}

// method to remove a customer by account number, if exists

static boolean removeCustomer(ArrayList<BankCustomer> customers,

int accountNum) {

for (int i = 0; i < customers.size(); i++) {
  
if (customers.get(i).getAcctNumber() == accountNum) {

// found, removing current customer

customers.remove(i);

return true; // found and removed

}
  
}

return false; // not found

}

// method to print customers

static void printCustomers(ArrayList<BankCustomer> customers) {

// displaying heading

System.out.printf("%-15s %-15s %-15s\n", "Customer Name",

"Account Number", "Account Balance");

// looping and printing each customer's name, acc num and balance

for (BankCustomer c : customers) {
  
System.out.printf("%-15s %-15d $%-14.2f\n", c.getName(),
  
c.getAcctNumber(), c.getBalance());
  
}

System.out.println("-----------------------------------------------\n");

}

// main method

public static void main(String[] args) {

// creating an array list of BankCustomer

ArrayList<BankCustomer> accounts = new ArrayList<BankCustomer>();

// scanner to read user input

Scanner scanner = new Scanner(System.in);

int ch = 0;

// looping until ch is 4

do {
  
// displaying menu
  
menu();
  
// inside try with multiple catches block, getting and processing
  
// user input
  
try {

System.out.print("Enter your choice: ");

//reading choice

ch = Integer.parseInt(scanner.nextLine());

System.out.println();

if (ch == 1) {
  
//reading details for bank customer
  
System.out.print("Enter name: ");
  
String name = scanner.nextLine();
  
System.out.print("Enter account number: ");
  
int accNum = Integer.parseInt(scanner.nextLine());
  
System.out.print("Enter balance: ");
  
double balance = Double.parseDouble(scanner.nextLine());
  
  
  
//creating a customer, will throw BCException if any detail is invalid
  
BankCustomer cust = new BankCustomer(accNum, balance, name);
  
//if no exception occurred, adding to the list and displaying the result
  
if (addCustomer(accounts, cust)) {

System.out.println("Success!");

} else {

System.out

.println("Customer with same account number already exists!");

}
  
} else if (ch == 2) {
  
//fetching an account number, removing customer
  
System.out.print("Enter account number: ");
  
int accNum = Integer.parseInt(scanner.nextLine());
  
if (removeCustomer(accounts, accNum)) {

System.out.println("Success!");

} else {

System.out

.println("Customer with given account number does not exist!");

}
  
} else if (ch == 3) {
  
//printing customers
  
printCustomers(accounts);
  
}

} catch (BCException e) {

//BCException is occurred

System.out.println(e.getMessage());

} catch (Exception e) {

//exception due to non numeric input

System.out.println("Invalid input!");

}
  
} while (ch != 4);

}

}

Answer 1

ANSWER:-

CODE AFTER REARRANGEMENT:-

import java.util.ArrayList;
import java.util.Scanner;

public class Bank {
   /**
   * Add and read bank information to the user.
   * @param arg A string, double and int array containing
   * the command line arguments.
   * @exception Any exception
   * @return an arraylsit of bank customers
   */

   // method to display the menu
   static void menu() {
       System.out.println("\n1. Add a bank customer");
       System.out.println("2. Remove a bank customer");
       System.out.println("3. Print all bank customers");
       System.out.println("4. Quit");
   }

   // method to add a customer in sorted order of account number into an array
   // list. returns true if addition is successful, else false
   static boolean addCustomer(ArrayList<BankCustomer> customers,BankCustomer newCustomer) {
       // looping and finding the proper position to add
       for (int i = 0; i < customers.size(); i++) {
           // checking if new customer can be added to index i
           if (newCustomer.getAcctNumber() < customers.get(i).getAcctNumber()) {
               // adding to index i
               customers.add(i, newCustomer);
               return true; // success
           } else if (newCustomer.getAcctNumber() == customers.get(i).getAcctNumber()) {
               // duplicate found, returning false
               return false;
           }
       }
       // adding to the end, if still not added
       customers.add(newCustomer);
       return true; // success
   }
   // method to remove a customer by account number, if exists
   static boolean removeCustomer(ArrayList<BankCustomer> customers,int accountNum) {

       for (int i = 0; i < customers.size(); i++) {
           if (customers.get(i).getAcctNumber() == accountNum) {
               // found, removing current customer
               customers.remove(i);
               return true; // found and removed
           }
       }
       return false; // not found
   }
   // method to print customers
   static void printCustomers(ArrayList<BankCustomer> customers) {
       // displaying heading
       System.out.printf("%-15s %-15s %-15s\n", "Customer Name","Account Number", "Account Balance");
       // looping and printing each customer's name, acc num and balance
       for (BankCustomer c : customers) {
           System.out.printf("%-15s %-15d $%-14.2f\n", c.getName(),          
           c.getAcctNumber(), c.getBalance());      
       }
       System.out.println("-----------------------------------------------\n");
   }
   // main method
   public static void main(String[] args) {
       // creating an array list of BankCustomer
       ArrayList<BankCustomer> accounts = new ArrayList<BankCustomer>();
       // scanner to read user input
       Scanner scanner = new Scanner(System.in);
       int ch = 0;
       // looping until ch is 4
       do {
           // displaying menu
           menu();
           // inside try with multiple catches block, getting and processing
           // user input
           try {
               System.out.print("Enter your choice: ");
               //reading choice
               ch = Integer.parseInt(scanner.nextLine());
               System.out.println();
               int accNum;
               // use switch instead if-else if,
               // using switch case for menu is better.
               switch(ch) {
                   case 1:
                       //reading details for bank customer
                       System.out.print("Enter name: ");
                       String name = scanner.nextLine();
                       System.out.print("Enter account number: ");
                       accNum = Integer.parseInt(scanner.nextLine());
                       System.out.print("Enter balance: ");
                       double balance = Double.parseDouble(scanner.nextLine());
                       //creating a customer, will throw BCException if any detail is invalid
                       BankCustomer cust = new BankCustomer(accNum, balance, name);
                       //if no exception occurred, adding to the list and displaying the result
                       if (addCustomer(accounts, cust)) {
                           System.out.println("Success!");
                       } else {
                           System.out.println("Customer with same account number already exists!");
                       }  
                       break;      
                   case 2:              
                       //fetching an account number, removing customer              
                       System.out.print("Enter account number: ");
                       accNum = Integer.parseInt(scanner.nextLine());                  
                       if (removeCustomer(accounts, accNum)) {
                           System.out.println("Success!");
                       } else {
                           System.out.println("Customer with given account number does not exist!");
                       }
                       break;              
                   case 3:              
                       //printing customers              
                       printCustomers(accounts);
                       break;              
               }
           } catch (BCException e) {
               //BCException is occurred
               System.out.println(e.getMessage());
           } catch (Exception e) {
               //exception due to non numeric input
               System.out.println("Invalid input!");
           }
       } while (ch != 4);
   }
}

NOTE:- I have not changed anything in the code's logic. I replaced if-else if with switch case. And gave indentation properly. So, you will get output as before. If you have any doubts, please comment below.

   THUMBS UP!!!! THANK YOU!!!!