Java-超级通话问题

Question

I'm new here, so some of my formatting may be odd.

I'm having some trouble calling a super constructor. Every time I compile my runner class, I'm getting a few errors:

.class expected" or "; expected

What's going on here?

(Code)

(Compiler output)

Answer 1

You need to call your super-constructor like this:

super(y,m,d);

Of course, that begs the question where those three values are supposed to come from. Probably you want to add three parameters to your own constructor:

public DateDriver(int y, int m, int d){
   super(y,m,d);
}

But: Why would you want to extend Date in the first place?

Answer 2

You can't declare variables inside the parameter section of a call to super() ;

Perhaps what you need is:

public DateDriver(int y, int m, int d) {
    super(y, m, d);
}

Then when you construct the DateDriver object in your main() method, you pass in values for y , m and d .

Answer 3

super(int x, int x, int d); does not make sense. It looks like you're trying to declare them while you're passing them in? If there exists a constructor in date with three int parameters, then you have to overload that one... not the no-parameter constructor:

public DateDriver(int y, int m, int d) {
    super(y, m, d);
}

Answer 4

Right syntax is

DateDriver()
{
   super(x, y, z);
   /* other code */
}

Always keep first line for a constructor call. If you want to make constructor chaining or you want to call parent class constructor.

example :

//for constructor chaining
DateDriver()
{
   this(x, y, z);
}
// for super call
DateDriver()
{
   this(x, y, z);
}