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Re: Using WMI to get hardware information

Randor 12-Jun-09 8:36

12-Jun-09 8:36

See if this works for you:

...
VARIANT v;
CIMTYPE ableugh;
hr = classObj->Get(L"Capacity", 0, &v, &ableugh, 0);
VariantChangeType(&v, &v, 0, VT_UI8);
ULONGLONG ui64Val = v.ullVal;
...

Best Wishes,
-David Delaune

Re: Using WMI to get hardware information

Anthony Mushrow15-Jun-09 0:50

Anthony Mushrow

15-Jun-09 0:50

Thanks for the help, VariantChangeType seems to be what I need. All I have to check for now is if the variant is NULL. CIMTYPE might come out as a string, but the variant could still be NULL, hr is okay and VariantChangeType doesn't complain, but when you try to get the BSTR kaboom!

My current favourite word is: Delicious!

-SK Genius

Game Programming articles start -here[^]-

Re: Using WMI to get hardware information

Stuart Dootson12-Jun-09 13:00

12-Jun-09 13:00

VariantChangeType[^] - just a string conversion under the hood, but you don't have to do the work yourself!

Use

::VariantChangeType(&ableugh, &ableugh, 0, VT_UI8);

and then V_UI8(&ableugh) should yield the result you want.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: Using WMI to get hardware information

Anthony Mushrow15-Jun-09 0:46

Anthony Mushrow

15-Jun-09 0:46

That works out pretty good, thanks.

My current favourite word is: Delicious!

-SK Genius

Game Programming articles start -here[^]-

How to avoid if else...

vikasvds12-Jun-09 3:40

12-Jun-09 3:40

Hello,

previously i have posted in wrong forum.
Problem is - User can input any number, program need to take decision based on inputs.

Let suppose input is stored in variable n;
based on value of n some function will be called.
program logic can be -

if(n > 1 && n < 10 )
callfun1();
if(n > 11 && n < 20 )
callfun2();
if(n > 25 && n < 30 )
callfun3();
if(n > 33 && n < 38 )
callfun4();
if(n > 1 && n < 10 )
callfun5();
.
.
.
and so on
if(n > minlimit && n < maxlimit )
callfunX();

Is there any easy way to avoid if else chain to do similar work.
Or is there any way to change the limits in if condition at some central place something using #define.

Please provide your inputs/help to help me finding other ways to optimize programming.

Thank
Vikas

vicky

Re: How to avoid if else...

harold aptroot12-Jun-09 4:05

12-Jun-09 4:05

You could arrange them in such a way that they effectively do a binary search. That wouldn't bring the total number of tests down but it would run faster (singe every time execution flows through it it can only take 1 path, so O(log n) steps instead of O(n))

Or you could fill a giant array with function pointers for O(1) time.

Or maybe you could change the functions to not need to be selected anymore (using funny bit magic if necessary) but whether that's possible depends on the function of course.

Re: How to avoid if else...

KarstenK12-Jun-09 4:21

12-Jun-09 4:21

a little help is the use of the keyword else Blush | :O

Blush | :O

if(n > 1 && n < 10 )
{
callfun1();
}
else if(n > 11 && n < 20 )
....

and sort it so that the most likely cases coming first.

AFAIK the compiler resolves switch in a similar way.

Best is the use of enums. Cool | :cool:

Cool | :cool:

Press F1 for help or google it.
Greetings from Germany

led mike12-Jun-09 4:23

12-Jun-09 4:23

You ignored the responses you got on this question the first time. Reposting is rude. Perhaps you can explain why you ignored the previous responses and still reposted the same question.

vikasvds14-Jun-09 21:48

14-Jun-09 21:48

I am very sorry for my re-post.

I have re-posted my question because at other discussion thread i was getting responses in terms of C# and .Net, but i need response in terms of pure C.

I have not done it intentionally, because of web page movement by mistake i've clicked at C# discussion link and posted the question instead of C/C++ category.

Thank
Vikas

vicky

led mike15-Jun-09 5:10

15-Jun-09 5:10

vikasvds wrote:
I am very sorry for my re-post.

Ok, but have you begun to understand that OOD/OOP has solutions to writing conditional code?

Re: How to avoid if else...

molesworth12-Jun-09 4:30

12-Jun-09 4:30

You probably need to take a step back, and think about what you're trying to achieve, and lay it out in a more logical pattern. Perhaps you can convert the value 'n' into a unique parameter for a switch statement.

There's also nothing wrong with using "else" so I'm not sure why you'd want to avoid it...

There are three kinds of people in the world - those who can count and those who can't...

Re: How to avoid if else...

led mike12-Jun-09 4:35

12-Jun-09 4:35

molesworth wrote:
There's also nothing wrong with using "else" so I'm not sure why you'd want to avoid it...

Here are some quotes from Kent Beck in his book Implementation Patterns[^]

If/then and switch statements are the simplest form of instance –specific behavior….
The more paths through a program the less likely the program is to be correct….The proliferation of conditionals reduces reliability….This problem is compounded when conditionals are duplicated.

These problems can all be eliminated by converting the conditional logic to messages, either with subclasses or delegation.

Re: How to avoid if else...

molesworth12-Jun-09 6:19

12-Jun-09 6:19

led mike wrote:
The more paths through a program the less likely the program is to be correct

Aye, that's very true, and anything that can reduce complexity will also reduce the likelihood of bugs, and improve readability and, more importantly, testability.

However, sometimes there's no way to improve on an if/else construct, and when used sensibly they're the right tools for the job. When you get into a morass of nested if/elseif/elseif... blocks, then you certainly do introduce problems.

Sheesh! Next thing you'll be telling me "goto" is a bad idea Smile | :)

Smile | :)

There are three kinds of people in the world - those who can count and those who can't...

Re: How to avoid if else...

CPallini12-Jun-09 6:42

12-Jun-09 6:42

I wouldn't subclass a if.
Big Grin | :-D

Big Grin | :-D

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: How to avoid if else...

led mike12-Jun-09 8:23

12-Jun-09 8:23

Why not? It's simple

class MyIf : public if
{
};

IT'S FRIDAY!!!!! Beer | [beer]

Beer | [beer]

Re: How to avoid if else...

CPallini12-Jun-09 22:39

12-Jun-09 22:39

And now saturday here Beer | [beer]

Beer | [beer]

Beer | [beer]

:pizza:

Beer | [beer]

Beer | [beer]

:whisky:

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: How to avoid if else...

led mike15-Jun-09 5:08

15-Jun-09 5:08

Wow, why would someone vote this a '1'? OMG | :OMG:

OMG | :OMG:

WTF | :WTF:

Re: How to avoid if else...

CPallini15-Jun-09 8:39

15-Jun-09 8:39

~~I suppose it is a personal attack against pizza , so, basically, ignorance...~~

[added]

led mike wrote:
Wow, why would someone vote this a '1'?

...when is available a really idiotic post to target [^]? Laugh | :laugh:

Laugh | :laugh:

[/added]

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: How to avoid if else...

Lutosław12-Jun-09 8:31

12-Jun-09 8:31

molesworth wrote:

There's also nothing wrong with using "else" so I'm not sure why you'd want to avoid it...

Adding elses to this code would dramatically change it's flow. Note that for n in a range (1,10) all callfuncs would be called.

Greetings - Jacek Gajek

Re: How to avoid if else...

CPallini12-Jun-09 5:46

12-Jun-09 5:46

Have you something personal against if-else?

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: How to avoid if else...

vikasvds15-Jun-09 2:32

15-Jun-09 2:32

CPallini wrote:
Have you something personal against if-else?

Yes, i don't like if-else
I hate them Dead | X|

Dead | X|

vicky

Re: How to avoid if else...

CPallini15-Jun-09 2:59

15-Jun-09 2:59

Try

#define WHATEVER_YOU_LIKE_AS_IF     if
#define WHATEVER_YOU_LIKE_AS_ELSE   else

and then, for instance

WHATEVER_YOU_LIKE_AS_IF (i>0 && i<10)
//..
WHATEVER_YOU_LIKE_AS_ELSE WHATEVER_YOU_LIKE_AS_IF (i>11 && i<20)
//..
//...

Poke tongue | ;-P

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Re: How to avoid if else...

Arun Singh K13-Jun-09 1:18

13-Jun-09 1:18

You can try something like this

int func1()
{
return 0;
}
int func2()
{
return 0;
}

typedef int (*funcptr)();
struct condition
{
int low;
int high;
funcptr func;
};

condition arr[] = {
{ 10, 20, func1 },
{ 20, 30, func2 } // Can add more data here
};

int n=17;

for (int i=0;i<2;++i)
{
if (n > arr[i].low && n < arr[i].high)
{
arr[i].func();
// If you want you can break here
}
}

-Arun

Re: How to avoid if else...

vikasvds14-Jun-09 21:30

14-Jun-09 21:30

Thank you very much all of your response,

The approach Arun has suggested is i think the way i was looking for as best and fasted approach.

Thanks Arun to help me suggesting this approach, it's really nice and definitely fastest method uses full potential of C/C++ language.

Thanks again.
Vikas

vicky

Re: How to avoid if else...

vikasvds14-Jun-09 21:32

14-Jun-09 21:32

One more advantage of this method i can change limits any time at one location for any if condition.

So to change the limits i need to see only at one place.

Thanks
Vikas

vicky

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