Nick Sabalausky wrote:
static void Main(string[] args)
{
Foo f;
if(args.Count() > 2) { f = new Foo(); }
if(args.Count() > 2)
{
f.bar(); // ERROR: Use of unassgned local variable 'f'
}
Foo f2;
createFoo(ref f2); // ERROR: Use of unassgned local variable 'f2'
f2.bar();
}
static void createFoo(ref Foo f)
{
f = new Foo();
}
---------------------------------------------
The first one is rather strange coding though and makes it easy to hide
errors anyway. And the second one's a tad odd too, plus I don't see any harm
in solving that with "Foo f2=null": it would at least be a hell of a lot
better than the compiler doing that very same "=null" automatically. I know
Walter doesn't agree, but I'd much rather have a few slightly inconvinient
false positives (or would it really be a false negative?) than even a mere
possibility for a hidden error.
The second one is an error; createFoo might use its argument before
assigning. You should have marked its argument as out instead, which
would not yield an error.
In point of fact, that's a common pattern in C#. Dictionaries define a
method bool TryGetValue(key, out value):
DateTime date;
if (dict.TryGetValue("key", out date))
{
// use date
}
