java - 如何更改不同类的主方法中的值

Question

我正在创建一个具有 ATM 类的程序，其中有一个支票和储蓄帐户，可以根据用户在起始类的主要方法中输入的内容进行更改。由于某种原因，当用户输入从其帐户存入/取款的金额时，数学已完成，但该值并未存储。因此，当我去显示帐户余额时，两个帐户都处于其起始值。

public class ATM {

private double cheqBal;
private double savingsBal;
private String bankName;

public ATM(double cheq, double savings, String name) {
    cheqBal = cheq;
    savingsBal = savings;
    bankName = name;
}

public double getCheq() {
    return cheqBal;
}
public double getSavings() {
    return savingsBal;
}
public String getName() {
    return bankName;
}

public void setCheq(double cheq) {
    cheqBal = cheq;
}
public void setSavings(double savings) {
    savingsBal = savings;
}
public void setName(String name) {
    bankName = name;
}

public double depositCheq(double cheq) {
    if (cheq < 0) {
        System.out.println("Sorry you cannot do that!");
    } else {
        cheqBal += cheq;
    }
    System.out.println(getCheq());
    return cheqBal;
}

有一个 ATM 类，其中包含存款/取款的方法。我只展示了存款查询方法。

double savBal = 500;
        double cheqBal = 1000;

        ATM bank1 = new ATM(cheqBal, savBal, "BMO");

        String userChoice = JOptionPane.showInputDialog("1: Deposit Cheqings \n2: Deposit Savings \n"
                + "3: Withdraw Cheqings \n4: Withdraw Savings \n5: Show Balance\n6: Exit");
        int choice = Integer.parseInt(userChoice);

        if (choice == 1) {
            String cheqIn = JOptionPane.showInputDialog("How much would you like to deposit?: ");
            bank1.depositCheq(Double.parseDouble(cheqIn));
            cheqBal = bank1.getCheq();
        } else if (choice == 2) {
            String savIn = JOptionPane.showInputDialog("How much would you like to deposit?: ");
            bank1.depositSavings(Double.parseDouble(savIn));
            savBal = bank1.getSavings();
        } else if (choice == 3) {
            String cheqOut = JOptionPane.showInputDialog("How much would you like to withdraw?: ");
            bank1.withdrawCheq(Double.parseDouble(cheqOut));
            cheqBal = bank1.getCheq();
        } else if(choice == 4){
            String savOut = JOptionPane.showInputDialog("How much would you like to withdraw?: ");
            bank1.withdrawSavings(Double.parseDouble(savOut));
            savBal = bank1.getSavings();
        }else if(choice == 5){
            bank1.toString();
        }else if(choice == 6){
            break;

有main方法。当我点击 1 存钱时，它不会重复我点击 5 显示余额时存入的金额。 (所有主要方法都在循环中，因此它会一直持续到退出)。

抱歉，代码量较大，希望大家理解我的问题并提供帮助!

Answer 1

每次运行循环时，您都会构造一个新的 ATM 对象，并将起始值传递给构造函数，因此您将显示这个新对象的值，而旧对象将被销毁。