java - 意外类型+非静态变量 this 无法从静态上下文错误中引用？

Question

我的代码无法编译。如何解决这些错误？

import java.util.*;
public class BankAccount{
private double balance;

public BankAccount(double b) {
    balance = b;
}

public double getBalance(){
    return balance;
}

public void deposit(double d){
    balance += d;
}

public boolean withdraw(double d){
    if(d > balance){
        return false;
    } else {
        balance -= d;
        return true;
    }
}
public class SavingsAccount extends BankAccount{
    private double interest;
    public SavingsAccount(double k, double inRate){
        super(k);
        interest = inRate;
    }

    public void gainInterest(){
        super.getBalance() = super.getBalance() * interest;
    }
}
public static void main(String[] args) {
    SavingsAccount test = new SavingsAccount(1000, .05);
    test.gainInterest();
    System.out.println(test.getBalance());

}

以下错误是

I get the unexpected type error at super.getBalance() = super.getBalance() * interest; and the "non-static variable this cannot be referenced from a static context" at SavingsAccount test = new SavingsAccount(1000, .05);

Answer 1

您无法为方法分配值。

您需要将结果分配给变量或将结果传递给另一个方法，在这种情况下您可以使用deposit，例如...

public void gainInterest(){
    deposit(super.getBalance() * interest);
}