子類名稱提示錯誤，不知道為什么，求大神幫看看
主程序
package app;
public class App {
public static void main(String[] args) throws Exception {
Auto audi = new Auto(1,"Audi A4",500,4,0);
}
}
父類
package app;
public class Auto {
int num;
String name;
int price;
int passengers;
int carry;
public ?Auto(int newnum,String newname,int newprice,int newpassengers,int newcarry) {
num = newnum;
name = newname;
price = newprice;
passengers = newpassengers;
carry = newcarry;
System.out.println(num+". ?"+name+" ?"+price+" yuan/perday ? passenge:"+passengers);
}
}
子類
package app;
public class AudiA4 extends Auto{
}
子類名稱提示錯誤：
Implicit super constructor Auto() is undefined for default constructor. Must define an explicit constructor
這是為什么？
2019-08-15
類已經定義了一個有參的構造函數并且父類中沒有默認的無參構造方法，此時編譯器不會為你調用默認的構造函數?
當子類繼承時，必須在自己的構造函數顯式調用父類的構造函數，自己才能確保子類在初始化前父類會被實例化?