Hello!

Can I use if expression in following way, or is it an error?:

void func(char[] str) {
	if (str !is null && str=="somestring") {
		... some code ...
	}
}

or should I rather use:
void func(char[] str) {
	if (str !is null)
		if (str=="somestring") {
			... some code ...
		}
}

The second way is more explicit and makes code unreadable soon...

I can find clear answer in docs...

BR
Marcin Kuszczak
(Aarti_pl)

Aarti_pl wrote:
> Hello!
> 
> Can I use if expression in following way, or is it an error?:
> 
> void func(char[] str) {
>     if (str !is null && str=="somestring") {
>         ... some code ...
>     }
> }

It's ok, see: http://www.digitalmars.com/d/expression.html#AndAndExpression

"If the left operand, converted to type bool, evaluates to false, then the right operand is not evaluated."

Lutger pisze:
> Aarti_pl wrote:
>> Hello!
>>
>> Can I use if expression in following way, or is it an error?:
>>
>> void func(char[] str) {
>>     if (str !is null && str=="somestring") {
>>         ... some code ...
>>     }
>> }
> 
> It's ok, see: http://www.digitalmars.com/d/expression.html#AndAndExpression
> 
> "If the left operand, converted to type bool, evaluates to false, then the right operand is not evaluated."

Great.
Thanks for advice!

BR
Aarti_pl

Aarti_pl wrote:
> Lutger pisze:
>> Aarti_pl wrote:
>>> Hello!
>>>
>>> Can I use if expression in following way, or is it an error?:
>>>
>>> void func(char[] str) {
>>>     if (str !is null && str=="somestring") {
>>>         ... some code ...
>>>     }
>>> }
>>
>> It's ok, see: http://www.digitalmars.com/d/expression.html#AndAndExpression
>>
>> "If the left operand, converted to type bool, evaluates to false, then the right operand is not evaluated."
> 
> Great.
> Thanks for advice!

Also, for arrays "null" is just an empty array, so you don't need the first part: 'if (str == "something")' works just fine even if 'str' is null (unlike with classes).
(A while back some people were complaining about this, but I don't think this behavior is likely to change)

Frits van Bommel wrote:
> Aarti_pl wrote:
>> Lutger pisze:
>>> Aarti_pl wrote:
>>>> Hello!
>>>>
>>>> Can I use if expression in following way, or is it an error?:
>>>>
>>>> void func(char[] str) {
>>>>     if (str !is null && str=="somestring") {
>>>>         ... some code ...
>>>>     }
>>>> }
>>>
>>> It's ok, see: http://www.digitalmars.com/d/expression.html#AndAndExpression
>>>
>>> "If the left operand, converted to type bool, evaluates to false, then the right operand is not evaluated."
>>
>> Great.
>> Thanks for advice!
> 
> Also, for arrays "null" is just an empty array, so you don't need the first part: 'if (str == "something")' works just fine even if 'str' is null (unlike with classes).
> (A while back some people were complaining about this, but I don't think this behavior is likely to change)

If you're referring to me, I wasn't complaining about this behaviour at all, this behaviour is great, I hope it never changes.

Regan