java - 不断收到预期的错误类、接口或枚举

Question

我看不出这堂短课有什么问题。我得到 8 个类、接口或枚举预期错误。谢谢

public class BankAccount {
public BankAccount {
    private double balance = 0;
}
public BankAccount(double balanceIn) {
    private double balance = balanceIn;
}

public double checkBalance {
    return balance;
}

public void deposit(double amount) {
    if(amount > 0) balance += amount;
}

public void withdraw(double amount) {
    if(amount <= balance) balance -= amount;
}
}

Answer 1

您在构造函数中声明了一个修饰符和字段。把它放在ctor外面

public BankAccount(double balanceIn) {
    private double balance = 0;
}

应该

public class BankAccount
{
    private double balance = 0;
    public BankAccount(){}
}

public BankAccount {
    private double balance = 0;
}

也是错误的..它不是您缺少 () 并删除的构造函数

private double balance = 0;