无法更新双倍（余额）

Question

“我正在尝试制作一个银行应用程序，每次您输入存款或取款时都会更新余额。我的菜单和其他一切都运行良好，但在打印出最终余额时，余额始终保持在 5000.00。我哪里做错了？”

            double balance = 5000.00;

                    switch(menu){

                            case 'd': case 'D':
                                double deposit = depositFunds(balance); 
                                break;

                            case 'w': case 'W':
                                double withdrawl = withdrawFunds(balance);
                                break;

                            case 'b': case 'B':
                                checkBalance(accountNumber, balance);
                                break;

                    }//end of switch     

    }//end of main

     public static double depositFunds(double balance){

        Scanner input = new Scanner(System.in);

        System.out.print("\nEnter the amount of the deposit: ");

        double deposit = input.nextInt();

        double currentBalance = (balance + deposit);

        return currentBalance;

     }//end of depositFunds

     public static double withdrawFunds (double balance){

            Scanner input = new Scanner(System.in);

            double currentBalance;

            System.out.print("\nEnter the amount of the withdrawal: ");

            double withdrawal = input.nextInt();

            currentBalance = (balance - withdrawal);

            return currentBalance;

     }//end of withdrawFunds

     //Display the balance
     public static void checkBalance(int accountNumber, double balance){

            System.out.printf("\nAccount Number: %d has a current balance of: %.2f\n" , accountNumber , balance);

     }//end of checkBalance

Answer 1

改为这样做：

switch(menu){

                        case 'd': case 'D':
                            balance = depositFunds(balance); 
                            break;

                        case 'w': case 'W':
                            balance = withdrawFunds(balance);
                            break;

                        case 'b': case 'B':
                            checkBalance(accountNumber, balance);
                            break;

             }