无法应用父类中的构造函数 [英] Constructor in parent class cannot be applied

问题描述

我正在尝试编写一个采用不同形状地毯的程序，并使用子类中定义的某些变量创建一个地毯对象。我的代码是

I'm trying to code a program that takes different shapes of carpets and creates a carpet object with certain variables defined in the subclasses. My code is

public abstract class Carpet{

protected int area = 0;
protected double unitPrice = 0;
protected double totalPrice = 0.0;
protected String carpetID;

public Carpet(String id, double thisPrice){
    carpetID = id;
    unitPrice = thisPrice;
}

public String getCarpetId(){
    return carpetID;
}

public String toString(){
    String carpet = new String("\n" + "The CarpetId:\t\t" + getCarpetId() + "\nThe Area:\t\t" + area + "\nThe Unit Price\t\t" + unitPrice + "\nThe Total Price\t" + totalPrice + "\n\n");
    return carpet;
}

public abstract void computeTotalPrice();

}

且子类是

public class CircleCarpet extends Carpet{

private int radius;

public CircleCarpet(String id, double priceOf, int rad){
    radius = rad;
    super.unitPrice = priceOf;
    computeTotalPrice();

}

public void computeTotalPrice(){
    super.area = radius * radius * 3;
    super.totalPrice = area * unitPrice;
}


public String toString(){
    String forThis = new String("\nThe Carpet Shape:\tCircle\nThe radius:\t\t" + radius + "\n");
    return forThis + super.toString();
}

}

但每当我尝试编译子类我得到错误

But whenever I try to compile the subclass I get the error

11: error: constructor Carpet in class Carpet cannot be applied to given types;
public CircleCarpet(String ID, double priceOf, int rad){
                                                       ^


 required: String,double
  found: no arguments
  reason: actual and formal argument lists differ in length
1 error

Tool completed with exit code 1

我不知道如何解决这个问题。

I'm not sure what to do to fix it.

推荐答案

作为你的超级class没有 no-args默认构造函数，你需要使用 super（） 。这不一定是你的第一行子类构造函数。

As your super class doesn't have a no-args default constructor, you need to explicitly call your super class constructor from your sub-class constructor using super().Not that this has to be the first line in your sub-class constructor.

 public CircleCarpet(String ID, double priceOf, int rad){
    super(ID, priceOf)
    radius = rad;
    super.unitPrice = priceOf;
    computeTotalPrice();

}

建议：

遵循Java命名约定，变量名应为camelCase。 i。，在这种情况下， id 比 ID 更合适。

Follow Java naming conventions, variable names should be camelCase. i., in this case id is more appropriate than ID.

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