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(shù)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(shù)?
當子類繼承時，必須在自己的構造函數(shù)顯式調用父類的構造函數(shù)，自己才能確保子類在初始化前父類會被實例化?