在Java中更改字段值时遇到问题
因此,作为免责声明,我对编程非常陌生,可能遗漏了一些显而易见的东西。现在,我正在尝试创建两个名为draw()和deposit()的方法,这两个方法允许我更改字段currentBalance的值,但是,每次我尝试使用这两个方法更改currentBalance的值时,我都会使用方法getBalance()检查字段的值,并且始终保持不变在Java中更改字段值时遇到问题,java,Java,因此,作为免责声明,我对编程非常陌生,可能遗漏了一些显而易见的东西。现在,我正在尝试创建两个名为draw()和deposit()的方法,这两个方法允许我更改字段currentBalance的值,但是,每次我尝试使用这两个方法更改currentBalance的值时,我都会使用方法getBalance()检查字段的值,并且始终保持不变 class TradingService{ public class Trader { //This field stores the trad
class TradingService{
public class Trader {
//This field stores the trader's name
private String traderName;
//This field stores the trader's current balance
private double currentBalance;
//A constructor to create a Trader
public Trader(String traderName) {
this.traderName = traderName;
}
//This method gets returns the trader's name
public String getName() {
return traderName;
}
//This method set's the trader's name
public void setName(String traderName) {
this.traderName = traderName;
}
//This method decreases the trader's balance
public void withdraw(double withdrawAmount) {
this.currentBalance = (currentBalance - withdrawAmount);
}
//This method increases the trader's balance
public void deposit(double depositAmount) {
this.currentBalance = (currentBalance + depositAmount);
}
//This method returns the trader's current balance
public double getBalance() {
return currentBalance;
}
}
}
我正在使用DrJava,并在交互面板中测试我的代码。这是我的测试结果
> Trader t1
> t1 = new Trader("Bill")
Trader@22e1cbe4
> t1.deposit(10.0)
10.0
> t1.getBalance()
0.0
我已经做了我能想象的一切来修复代码,但是我没有主意了,我不认为在我的代码中再输入随机的东西3个小时会有什么效果
感谢您抽出时间阅读我的问题。下面的代码工作正常。我不确定Java博士是什么,但代码按预期工作
public class TradingService {
class Trader {
//This field stores the trader's name
private String traderName;
//This field stores the trader's current balance
private double currentBalance;
//A constructor to create a Trader
public Trader(String traderName) {
this.traderName = traderName;
}
//This method gets returns the trader's name
public String getName() {
return traderName;
}
//This method set's the trader's name
public void setName(String traderName) {
this.traderName = traderName;
}
//This method decreases the trader's balance
public void withdraw(double withdrawAmount) {
this.currentBalance = (currentBalance - withdrawAmount);
}
//This method increases the trader's balance
public void deposit(double depositAmount) {
this.currentBalance = (currentBalance + depositAmount);
}
//This method returns the trader's current balance
public double getBalance() {
return currentBalance;
}
}
public static void main(String[] args) {
TradingService service = new TradingService();
TradingService.Trader trader = service.new Trader("trader");
System.out.println("Balance before deposit:\n" + trader.getBalance());
trader.deposit(10.00);
System.out.println("Balance after deposit:\n" + trader.getBalance());
}
}
输出:
Balance before deposit:
0.0
Balance after deposit:
10.0
“交易者”班看起来不错,为我工作。但是你有一个“Trader”,在“TradingService”类中是一个公共类,我想可能这个类没有编译,你正在执行一个旧文件,你可以像内部类一样使用“Trader”类来尝试这个
class Trader {
//This field stores the trader's name
private String traderName;
//This field stores the trader's current balance
private double currentBalance;
//A constructor to create a Trader
public Trader(String traderName) {
this.traderName = traderName;
}
//This method gets returns the trader's name
public String getName() {
return traderName;
}
//This method set's the trader's name
public void setName(String traderName) {
this.traderName = traderName;
}
//This method decreases the trader's balance
public void withdraw(double withdrawAmount) {
this.currentBalance = (currentBalance - withdrawAmount);
}
//This method increases the trader's balance
public void deposit(double depositAmount) {
this.currentBalance = (currentBalance + depositAmount);
}
//This method returns the trader's current balance
public double getBalance() {
return currentBalance;
}
}
public class TradingService{
public static void main(String[] args)
{
Trader t = new Trader("test");
t.deposit(10);
System.out.print(t.getBalance());
}
}
看来它会起作用的。
Trader
class对我来说很合适。你能发布你实际运行测试、创建trader、调用getBalance()等的主要方法吗?我对Java博士不熟悉,但这可能是你忘记保存之类的愚蠢行为吗?除非你保存,否则代码实际上不会编译,所以没那么简单,很遗憾。@user6933987您确定发布的类与您试图运行的类完全相同吗?您的示例代码不能与您发布为Trader
的类一起工作,该类是TradingService
的内部非静态类,您不能像示例中那样直接实例化它。我下载了Dr.Java,没有外部类(TradingService
),您的代码按预期工作,并在调用getBalance()
后打印回10.0。非常感谢你!