无法应用父类中的构造函数

Question

我正在尝试编写一个程序，该程序采用不同形状的地毯，并使用子类中定义的某些变量创建地毯对象。我的代码是

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();

}

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();
}

}

但每当我试图编译子类时，我都会遇到错误

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

我不知道该怎么修理它。

Answer 1

由于您的超类没有< code >无参数默认构造函数，您需要使用super()从子类构造函数中显式调用您的超类构造函数。并不是说这必须是子类构造函数的第一行。

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

}

忠告：

遵循Java命名约定，变量名应该是camelCase。即，在这种情况下，< code>id比< code>ID更合适。