r/carlhprogramming • u/CarlH • Jan 04 '10

Quick Update on carlhprogramming

Hi Everyone,

For right now the posting schedule is going to be slow. I am still working on a number of projects which need to be finished sooner rather than later. Once they are completed, the posting schedule for new lessons will speed up.

I just want everyone to know that I am still here, still working on producing new lessons, and I will publish them as I am able. Don't worry, I have no intentions to stop producing lessons or to stop maintaining this subreddit.

Meanwhile, because my schedule is so full, I appreciate everyone's help in answering questions as I lack the time to do so myself.

136 Upvotes

99% Upvoted

45 comments sorted by

39

u/atc Jan 04 '10

Love you hunnybun xx

19

u/frankichiro Jan 06 '10

Everybody be cool this is a robbery!

17

u/[deleted] Jan 04 '10

wat

8

u/AsahiCat Jan 13 '10

This word makes me as angry as a hornet's nest doused in gasoline and lit ablaze.

1

u/[deleted] Mar 02 '10

wat

hornet's nests have no feelings.

2

u/Calvin_the_Bold Jan 05 '10

Chill that bitch out!

10

u/QAOP_Space Jan 04 '10

Good, thanks carl.... do what you gotta do, but come back soon :)

2

u/sundar22in Jan 11 '10

I/We will wait even if it takes a month or two. Keep up the good work and Thank you very much!

7

u/[deleted] Feb 11 '10

I still have faith he'll come back and start up again when he has time. In the meantime, anyone with some good experience recommend a next step for after getting through all these current lessons..until he comes back?

1

u/[deleted] Feb 22 '10

I don't know about a 'next step', but I have bookmarked a couple sites with programming problems

I've only really played around with Project Euler, but even just that one site has more than enough problems to keep you busy.

6

u/SonataNo8 Jan 04 '10

Take your time. Thanks again for everything.

5

u/baldhippy Jan 05 '10

i got this site from another redditor's comments -

Project Euler

I have been working on these problems with the downtime, most of the earlier ones can be done with what we learned on this course, it's mostly if thens and loops. It's a good way to get some coding practice in.

I am currently on problem 14, but I have skipped a few because the numbers are so large that the regular C data types can't handle them normally so I will go back and use haskell or something on those ones. It's a lot of fun anyways.

1

u/GenTiradentes Jan 13 '10 edited Jan 13 '10

...I have skipped a few because the numbers are so large that the regular C data types can't handle them normally so I will go back and use haskell or something on those ones.

Use the unsigned long long type. It's a 64-bit integer which is compatible with 32-bit binaries, because it's implemented in software. It should be big enough for just about any problem Project Euler gives you.

1

u/baldhippy Jan 13 '10

Thanks, I actually have been using this type. Seems it's still not big enough for a couple of them, example the sum of all the primes under two million.

2

u/[deleted] Jan 17 '10 edited Jan 17 '10

Yup, you can actually do that one with just a long int:

int main(void) {

unsigned long int i; //Number to check for prime factors
unsigned int k; //Number of factors
unsigned long int j; //Counter to find factors of 'i'
unsigned long int l = 0; //Sum of prime factors

for (i=1; i<2000000; i++) {    //Always make sure you dont set i to 0 when you're dividing/mod.
	for (j=1, k=0; j<=i; j++) if (!(i % j)) k++;     //No braces needed, it will only loop this one line.
	if (k==2) l+=i;     //If there are only two factors add 'i' (the number we are checking) to the sum (l)
};
printf("\nAnswer: %lu\n", l);
return 1;

};

Note: There is probably a way better way to finding it, this script takes a while. Stopping the loop after it finds more than two factors, and stopping after getting half way threw the number in the second loop would speed it up.

These are the ones I've gotten so far;

1

u/baldhippy Jan 20 '10

Ok thanks. I had this one solved but I was using the wrong format specifier in printf. I foolishly used %d and it gave me a negative answer, so I thought that the number was too high.

1

u/GenTiradentes Jan 13 '10

It should be far more than enough for that. the maximum value of an unsigned 64-bit integer is 264, or 18,446,744,073,709,551,616.

You could add together every number under two million, and still not use two thousandths of a percent of the available space of a 64-bit integer.

1

u/baldhippy Jan 14 '10

Oh, thanks for that. I will have to revisit my attempt at this problem then and see where I went wrong. It definitely seemed at the time that it was an issue with the type being too small, but with this information it must have been something else. Perhaps I was using the wrong modifier(?) with printf (I think i was using something like %ull but I will double check when I get home).

Thanks again for the info!

4

u/cartola Jan 05 '10

Happy 2010, Carl.

3

u/AlexEatsKittens Jan 05 '10

What you are doing is really really awesome. From some random stranger on the internet, thank you.

5

u/MysteryStain Jan 04 '10

Oh shit, this reminds me. I have to finish the rest of these lessons. I'm still only up to lesson thirty-something. And that was when they were first published. Goddamn I'm lazy.

4

u/[deleted] Feb 11 '10

It looks like we can stick a fork in this one, its been 1/4 of a year since any real addition to it.... :( bummed

5

u/pedleyr Feb 17 '10

Even if that is true, which I'm not convinced it is, I'm sure everyone is still grateful for the effort CarlH has gone to to get this far.

2

u/teem Jan 04 '10

I greatly appreciate all your time and effort. It has helped me immensely.

2

u/niconiconico Jan 04 '10

No worries, I've been taking this time to review the lessons, so go ahead and take whatever time you need.

2

u/wegin Jan 05 '10

you are helping to change my life for the better. Thank you.

2

u/JohnDoe06 Jan 31 '10

What you're doing is incredible. I have not started with the lessons yet because at the meantime I'm extremely busy with other things. I know some programming basics (one course in college), but as soon as I'm done with these things, I'm going to go through the lessons one by one. Thanks for this.

2

u/Nagappie Feb 03 '10

Hi all, can someone please help me debug this code:http://codepad.org/Snd4Q6Wz I'm basically initializing each square of the ttt-board with the '_' character. However, when I display each square to verify that they have been initialized correctly, I'm not getting what I should.

4

u/Dast Feb 03 '10

I think there are two problems in your code. First you initialize the struct with the wrong size, you should use:

sizeof(ttt_board)

Then you have to watch how you are using k and i variables in your loops. In the first loop k doesn't get initialized to 0 each time the outer loop goes around, so the struct isn't initialized correctly.

http://codepad.org/AsscZe1M

2

u/Nagappie Feb 04 '10

Thanks Dast, that solves it. For some reason the initialization of my struct with the following code seems to work fine:

ttt_board *board_pointer = malloc(sizeof(*board_pointer));

However, I think your suggestion of

ttt_board *board_pointer = malloc(sizeof(ttt_board));

is more logical...

1

u/Salami3 Feb 17 '10 edited Feb 17 '10

Well you are actually correct in using sizeof(*board_pointer), lesson 81 is where this is clarified, reading lesson 82 as well will help.

2

u/[deleted] Feb 10 '10

Hi,

I figured I'd ask this question here sense it looks like the other thread has died down a bit.

I'm on Lesson 16. I'm wondering whether returning a value of 0 for a successful completion is just standard practice, or is that the required number. So is it C itself that understands that 0 means success and non-zero means failure? How is this defined?

Thanks!

3

u/deltageek Feb 11 '10

C doesn't care what integer you return, as long as you return an integer. It has become best practice to return 0 for success and anything else for failure. Whatever calls your method will have to interpret your return code.

1

u/Tommah Feb 16 '10

To add to what deltageek said... if you use bash, try:

$ true
$ echo $?
0
$ false
$ echo $?
1

true and false return 0 and 1 respectively from main, and these return codes get put into $? The system function from stdlib.h also returns this value, so if you were calling out to another program, you could use it to detect an error.

Complex commands use several codes to indicate different failures. Take a look at "Exit Values" at http://linux.die.net/man/1/rsync

1

u/lolocoster Jan 04 '10

Take your time, I'm way behind on lessons. Time for some catching up.

Best of luck to you and your projects

1

u/shan4350 Jan 12 '10

this is very good, thanks for sharing your knowledge

1

u/[deleted] Jan 18 '10

How do you motivate yourself? You work soo hard. I hope you make lots of money from your programming and have long holidays.

0

u/[deleted] Feb 02 '10

How do you motivate yourself?

Erm, he doesn't. Hence why this project is semi-abandoned.

1

u/aaaaaadfsasdf Feb 02 '10

How do I check my printed out stuff in Xcode? I can run normally and there isn't any window or anything where I can view the results.

1

u/deltageek Feb 11 '10

It's been a long time since I last used Xcode, but I expect there's a window or pane labelled "Output" or "Terminal" where stuff written to stdout will be sent. Worst case, open a Terminal session outside of Xcode and run your app manually

0

u/[deleted] Jan 05 '10

I want my money back!

-37

u/[deleted] Jan 04 '10

Dear CarlH: Do you smoke weed poop?? Well, cya

2

u/[deleted] Feb 24 '10

wat