The Big Programming Thread - Page 216

On December 13 2012 01:47 Recognizable wrote:
Hey, I have a question. I understand why the following prints: MichaelLieberman. But I don't understand if I change line 4 from, x[0] + x[1] to i[0] + i[1] it prints: Mi.

n = ["Michael","Lieberman"]
def myFun(x):
	for i in x:
		return x[0] + x[1] # What happens when you change x to i?
print myFun(n)

On December 13 2012 06:46 adwodon wrote:
Hey guys,
Two questions, both completely separate so answer either if you can

1)
I was just thinking coming home from work, I come from a physics background not a comp sci one so I'm not aware of some of the basics. Anyway, I remembered a question I had at an interview a while back about finding powers of 2. I mentioned several ways including looking at the binary, if it has a single 1, its a power of two.

Just thinking about that again, it sounds straight forward but then I realized I actually don't know how I'd implement that, could anybody give me an example? C preferably but C++ / Java / Python / whatever non-obscure language is fine if it suits.

2)
It's been a while since I did anything website related (5+ years), I'm considering setting up a personal site with a blog element, essentially to act as an both an extension for my CV and a kind of notebook / progress measure for personal projects.

Is there any kind of IDE / package I should consider using? All I remember is Dreamweaver and I have no idea if thats still useful or if there are superior / solid alternatives or as its just a small site, if I'm better off just using Notepad++ and cranking it out by hand.

I'm guessing HTML / CSS are still the main things with a splash of Javascript, but for a blog section is it reasonable to write something yourself, are there libraries / things to make this straight forward? I don't want a template site, but at the same time I don't really want to spend the next 6 months writing something with barely any functionality and full of annoying bugs, as I'd be learning every step of the way. What sort of languages would I expect to learn? I know a bit of Ruby but that's all as far as what I would consider web languages.

If there are any good resources / websites then please do share, I could probably find out a lot of this by the powers of google but I find its often best to ask in a forum as you tend to get a more well rounded answer

Thanks in advance!

bool isPowerOfTwo(int value)
{
    return value && !(value & (value - 1)); //hint: value && [...] is there just because otherwise it would consider 0 to be a power of zero
}

On December 13 2012 06:46 adwodon wrote:
Hey guys,
Two questions, both completely separate so answer either if you can

1)
I was just thinking coming home from work, I come from a physics background not a comp sci one so I'm not aware of some of the basics. Anyway, I remembered a question I had at an interview a while back about finding powers of 2. I mentioned several ways including looking at the binary, if it has a single 1, its a power of two.

Just thinking about that again, it sounds straight forward but then I realized I actually don't know how I'd implement that, could anybody give me an example? C preferably but C++ / Java / Python / whatever non-obscure language is fine if it suits.

2)
It's been a while since I did anything website related (5+ years), I'm considering setting up a personal site with a blog element, essentially to act as an both an extension for my CV and a kind of notebook / progress measure for personal projects.

Is there any kind of IDE / package I should consider using? All I remember is Dreamweaver and I have no idea if thats still useful or if there are superior / solid alternatives or as its just a small site, if I'm better off just using Notepad++ and cranking it out by hand.

I'm guessing HTML / CSS are still the main things with a splash of Javascript, but for a blog section is it reasonable to write something yourself, are there libraries / things to make this straight forward? I don't want a template site, but at the same time I don't really want to spend the next 6 months writing something with barely any functionality and full of annoying bugs, as I'd be learning every step of the way. What sort of languages would I expect to learn? I know a bit of Ruby but that's all as far as what I would consider web languages.

If there are any good resources / websites then please do share, I could probably find out a lot of this by the powers of google but I find its often best to ask in a forum as you tend to get a more well rounded answer

Thanks in advance!

int ispow2(int num)
{
while(! (num%2)) num=num>>1; //slide the number over to the first bit
return !(num>>1); //if its the only bit in the number, then the number is a power of 2
}

int ispow2(int num)
{
int mask = 1;
while(mask) //this works because bitshifting using << will bitshift all the way to 0 when overflowed.
if(!(mask ^ num)) return true;
else mask = mask << 1;

return false;
}

On December 13 2012 07:18 tofucake wrote:
web design IDEs are the devil

On December 13 2012 07:03 heishe wrote:
On [1]. :

bool isPowerOfTwo(int value)
{
    return value && !(value & (value - 1)); //hint: value && [...] is there just because otherwise it would consider 0 to be a power of zero
}

I'll leave it to you to figure out why this works. Should be a nice exercise in bitwise-operations.

On December 13 2012 07:18 RoyGBiv_13 wrote:
2) Wordpress has become the defacto standard for blogs. You can also check out Svbtle, which looks pretty cool. It's way easier than it ever has been to set up a personal blog.

On December 13 2012 07:18 tofucake wrote:
web design IDEs are the devil

On December 13 2012 06:46 adwodon wrote:
I was just thinking coming home from work, I come from a physics background not a comp sci one so I'm not aware of some of the basics. Anyway, I remembered a question I had at an interview a while back about finding powers of 2. I mentioned several ways including looking at the binary, if it has a single 1, its a power of two.

Just thinking about that again, it sounds straight forward but then I realized I actually don't know how I'd implement that, could anybody give me an example? C preferably but C++ / Java / Python / whatever non-obscure language is fine if it suits.

int power_of_two(unsigned int x)
{
    return __builtin_popcount(x) == 1;
}

power_of_two:
	popcntl	%edi, %edi
	xorl	%eax, %eax
	cmpl	$1, %edi
	sete	%al
	ret

On December 13 2012 23:21 AmericanUmlaut wrote:
Why is checking single bits incredibly slow? Can't you just do sixteen bitwise shifts and use two variables to keep track of your current and max count of consecutive 1s?

On December 14 2012 02:23 gyth wrote:
There is probably an assembly instruction to do what you're looking for, or its complement.
http://en.wikipedia.org/wiki/Find_first_set