Instance vs Local Initialization

[vooose]

Consider

{
bool var;
if(var)
Console.WriteLine("var is true");
}

results in the compilation error

Use of unassigned local variable 'var'

If you make var an instance variable you don't get a compile error as
the variable is effectively 'initialized' to all zeros. Why can't local
variables behave in this manner?

It irritates me that I have to type

bool var=false;

Regards

 

[Jon Skeet [C# MVP]]

Consider

{
bool var;
if(var)
Console.WriteLine("var is true");
}

results in the compilation error

Use of unassigned local variable 'var'

If you make var an instance variable you don't get a compile error as
the variable is effectively 'initialized' to all zeros. Why can't local
variables behave in this manner?

They could - but it's better that they don't. In a way, the *downside*
is that you *can't* do this with instance variables.

The fact that you can't accidentally use a local variable before it's
been initialised is great IMO. I've seen plenty of bugs in C code which
does just that.

It irritates me that I have to type

bool var=false;

If you want to just not execute some code, don't include it in the
first place, or write:

if (false)

It's relatively rare that I find I have to initialise a local variable
with a value which isn't actually useful.

 

[vooose]

Thanks for your reply John. How about this case...

{
bool found=false;
foreach(string temp in arr)
{
if(temp == "hullo")
found=true;
}

if(!found)
//do not found stuff
}

I don't want to initialize found in this case (granted this isnt a big
deal but still...)

 

[vooose]

Sorry Jon for name typo in previous. One more thing...I didn't
understand what you meant by

If you want to just not execute some code, don't include it in the
first place, or write:

if (false)

with respect to my initial question. I would prefer a compilation
error for objects but not for primitives.

Regards

 

[Jon Skeet [C# MVP]]

Thanks for your reply John. How about this case...

{
bool found=false;
foreach(string temp in arr)
{
if(temp == "hullo")
found=true;
}

if(!found)
//do not found stuff
}

I don't want to initialize found in this case (granted this isnt a big
deal but still...)

Why not? It makes it more explicit what you want - which is actually to
be initialised to false.