[668] in java-interest
Re: Java compiler is trying too hard for me
daemon@ATHENA.MIT.EDU (Arthur van Hoff)
Wed Jul 12 17:42:04 1995
Date: Wed, 12 Jul 1995 13:15:11 -0800 (PDT)
From: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
Reply-To: Arthur van Hoff <Arthur.Vanhoff@Eng.Sun.COM>
To: Tientien Li <li@deming.Jpl.Nasa.Gov>
Cc: java-interest@java.Eng.Sun.COM
Hi Tientien,
> > > The Java compiler "javac" won't let me do the following type of code:
> > >
> > > class smartjavac {
> > > public void init() {
> > > int x;
> > > for (int i=0; i<3; i++) {
> > > if (i == 0) x = i;
> > > else if (i == 1) x = i;
> > > else x = i;
> > > }
> > > System.out.println("ValueOfX is " + x );
> > > }
> > > }
> >
> > Try giving x an initial value. The compiler may think that it is possible
> > that the loop may be executed 0 times, since compile-time determination
> > is not always possible.
> >
> > Dan Evans
> > dan.evans@peri.com
> >
>
> Dan,
>
> OK, I agree with you its a good idea to initialize variables. From now on,
> I'll try to init all local variable to make "javac" happy. However, this
> problem is a bit more complicated, e.g., the "javac" will let the following
> code thru:
>
> class smartjavac {
> int x; // x is now moved to outside....
> public void init() {
> for (int i=0; i<3; i++) {
> if (i == 0) x = i;
> else if (i == 1) x = i;
> else x = i;
> }
> System.out.println("ValueOfX is " + x );
> }
> }
>
> Looks like "javac" only check this condition for variables defined locally
> within the current function scope.
Instance variables are automatically initialized to 0 (or the equivalent
thereof).
Have fun,
Arthur van Hoff
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