Question

我试图通过main函数调用我的对象。因为它需要静态参考，但我不知道怎么做。有人可以告诉我，我做错了什么？

private double checking;
private double saving;


    public BankDisplay(double checking,double saving) // Constructor for subclass
    {
    checking=1000;
    saving=1000;

    }


    public void setChecking(double checking){
        this.checking=checking;
    }

    public double getChecking(){
        return checking;

    }

    public void setSaving(double saving){
        this.saving= saving;
    }

    public double getSaving(){
        return saving;

    }

BankDisplay checking1=new BankDisplay(checking, saving);
BankDisplay savings1= new BankDisplay(checking,saving);

当我尝试在main中打印对象checking1和saving1时，它显示＆＃34;不能为静态函数提供非静态引用＆＃34;。

Answer 1

     public BankDisplay(double checking,double saving) // Constructor for subclass
        {
        this.checking=checking;
        this.saving=saving;

        }

There is an error in constructor.


public static void main(String[] args){
   BankingDisplay d1 = new BankingDisplay(100.15,200.15);
   System.out.println(d1.getChecking());
}

Answer 2

你的构造函数的方法是错误的，它应该是：

public BankDisplay(double checking,double saving) // Constructor for subclass
    {
        this.checking = checking;
        this.saving = saving;
    }

您的课程中也应该有一个toString()功能，以便您正确打印对象。

如：

public String toString() {
    return String.format("Checking: %s\nSavings: %s\n", this.checking, this.saving);
}

像这样使用：

System.out.println(checking1.toString());

Answer 3

public class BankDisplay {
    private double checking;
    private double saving;

    public BankDisplay(double checking,double saving) // Constructor for subclass
    {
        this.checking= checking;
        this.saving= saving;
    }

    public void setChecking(double checking){
        this.checking=checking;
    }

    public double getChecking(){
        return checking;

    }

    public void setSaving(double saving){
        this.saving= saving;
    }

    public double getSaving(){
        return saving;

    }
}


public class Main {

    public static void main(String[]args){
        BankDisplay account1 = new BankDisplay(1000,100);
        System.out.println(account1.getChecking());
    }
}

这应该可以解决您的问题：D您在构造函数中需要this，因为您设置的是构造函数值，而不是您的私有变量。

我的主要功能中没有调用我的对象

3 个答案: