As in,

import std.stdio;
void main()
{
int i;
for (int i=0;i<2;i++)
writefln(i);
}

Should not have the compiler complained about it being declared twice?

I missed this one and it caused me. :-)

thanks,

josé

jicman wrote:
> As in,
> 
> import std.stdio;
> void main()
> {
> int i;
> for (int i=0;i<2;i++)
> writefln(i);
> }
> 
> Should not have the compiler complained about it being declared twice?
> 
> I missed this one and it caused me. :-)
> 
> thanks,
> 
> josé
> 
> 
No, the int i inside the for loop has a different scope.  This is the same as C++, and infact g++ doesn't even warn about i being hiding with -Wall on.
On a standards compilant C++ compiler (which MSVC by default is not) this will break
<code>
for (int i=0; i < 10; i++)
;
printf("%i\n", i);  // should be an error because i is no longer in scope.
</code>

D has the same scoping rules for "for" loops.

Brad

Most/all decent C++ compilers warn about this ...


<brad@domain.invalid> wrote in message news:d0lrc9$12oo$1@digitaldaemon.com...
> jicman wrote:
>> As in,
>>
>> import std.stdio;
>> void main()
>> {
>> int i;
>> for (int i=0;i<2;i++)
>> writefln(i);
>> }
>>
>> Should not have the compiler complained about it being declared twice?
>>
>> I missed this one and it caused me. :-)
>>
>> thanks,
>>
>> josé
>>
>>
> No, the int i inside the for loop has a different scope.  This is the
> same as C++, and infact g++ doesn't even warn about i being hiding
> with -Wall on.
> On a standards compilant C++ compiler (which MSVC by default is not)
> this will break
> <code>
> for (int i=0; i < 10; i++)
> ;
> printf("%i\n", i);  // should be an error because i is no longer in
> scope.
> </code>
>
> D has the same scoping rules for "for" loops.
>
> Brad

On Wed, 09 Mar 2005 16:43:34 +1300, brad wrote:

but this looks like it shouldn't be valid
(http://www.digitalmars.com/d/statement.html#block):

import std.stdio;
void main(char[][] args)
{
	int i = 25;
	{
		int args;
	}
	{
		int i = 15;
		writefln("in ",i);
	}
	for (int i=0; i<2; i++)
	{
		writefln("for ",i);
		for (int i=425; i<427; i++)
		{
			writefln("\tfor ",i);
		}
	}
	writefln("out ",i);
}


#outputs#
in 15
for 0
	for 425
	for 426
for 1
	for 425
	for 426
out 25
##

Ant

yeah, well, I was right... :-)

Ant says...
>
>On Wed, 09 Mar 2005 16:43:34 +1300, brad wrote:
>
>but this looks like it shouldn't be valid
>(http://www.digitalmars.com/d/statement.html#block):
>
>import std.stdio;
>void main(char[][] args)
>{
>	int i = 25;
>	{
>		int args;
>	}
>	{
>		int i = 15;
>		writefln("in ",i);
>	}
>	for (int i=0; i<2; i++)
>	{
>		writefln("for ",i);
>		for (int i=425; i<427; i++)
>		{
>			writefln("\tfor ",i);
>		}
>	}
>	writefln("out ",i);
>}
>
>
>#outputs#
>in 15
>for 0
>	for 425
>	for 426
>for 1
>	for 425
>	for 426
>out 25
>##
>
>Ant
>