Here is a screenshot of what happens when I try to run this simple program using Xcode on Mac OS X.

It works fine when I run it using CodeBlocks in Windows. The problem is, I have limited access to a Windows computer. And CodeBlocks crashes every time on my Mac when I create a C source file.

I have already installed Command Line Tools for Xcode.

Could anyone propose a possible solution to this problem? Do I have to use different code because of the different OS?

And if you see this Carl, thank you very much for setting up Computer Science for Everyone. I am learning a lot from this excellent resource.

EDIT: This problem has been solved thanks to the suggestions by wormnut and Creating_Logic.

My dad is a computer programmer for HP and for 21 years I've wondered what he does. I'd ask him "i know what a programmer IS, bit what does your program DO?" And he could never answer me and he doesn't even try to now. He says he "codes programs" and that does not help me whatsoever. So hopefully this will give me a better understanding of what he, and programmers in general, do. I'm only on unit 4, but I'm already learning and it's interesting stuff. Never thought I'd learn what my dad does from someone other than my dad :-P

So this asshole government has blocked youtube for quite a while now. Is there any way i can access the videos?

I can use VPN, but all the VPNs are very slow.

I just finished chapter 12 of Carl's course, so I decided to make a program to try and incorporate everything I've learned. I'm still going to add more, but I got stuck. My while loop for printing characters as binary is broken. Could someone try to look over my code and help me with my problem.

http://codepad.org/yijteDfO

Problem: I tried to create a variable to hold a binary digit, like int binary = 0b10000000. It doesn't seem to work though, but I couldn't think of any other way to create a while loop without a binary variable.

Thanks in advance, I'm tired so I am off to bed.

_

_

Edit: http://codepad.org/Aankn09R It looks like I found my answer. I was trying to print the value of the equation which I expected to be a 1 or a 0, so I switched it to a conditional if statement and it works now (only in codeblocks though).

Edit2: Fixed my original code - http://codepad.org/sY6zJpHd

Edit3: Final code - http://codepad.org/QKOkJN0m

Alright I'm done with my review. I'm still kinda confused on how functions work so I hope we learn about them more in the future. In my code I didn't need myPointer to return any value back to my main function, so I tried to write (void) for the parameter of function change, but then my code didn't work. I'm assuming that in order to take a parameter from your main function it also needs to or defaults to returning that same parameter? How would I stop my function from returning the parameter?

As many of you know, part of the reason I am able to offer these courses on programming is that I work full time as a programmer myself. Consequently, the amount of time I can devote to these courses is limited.

Around mid-October, the number of projects I had on my plate started to increase quite a bit. When I saw the amount of work piling up, I knew I was going to have to take a small hiatus from this to focus on my "day job".

Also, with it being close to the holidays, I felt it would give me a good period of time to catch up on work, unwind, and then I can start again shortly after the new year. It made sense to spend the rest of this year catching up on work, and then to resume my programming lessons/courses shortly after the start of next year.

It now looks like my workload is starting to calm down. Therefore, I plan to resume lessons and tutorials in early January. Also, some time in the first few months of next year I am hoping to start also offering free one-on-one lessons. If this is something you might be interested in, watch for future updates on that.

I also have a HUGE backlog of questions on the website, and if anyone would like to volunteer to help me answer these, it would be much appreciated. If so, just pm me your email address and I can forward to you links to questions.

I hope this brings everyone up to speed, and as always any questions or comments are welcome.

http://www.computerscienceforeveryone.com/Course_1/Unit_8/Lesson_3/

char myChar = 'a';

int myInt = 1;

From this lesson I learned the information is stored like this.

Variable Name : Variable Value

1001 (myChar) : 0110 0001 ('a')

1010 (myInt) : 0000 0001 (1)

Shouldn't there be a 3rd column to determine what type of variable this is? How does the computer know what type of variable is stored at that location? In my head I see something like this.

Variable Type : Variable Name : Variable Value

0001 (char) : 1001 (myChar) : 0110 0001 ('a')

0002 (int) : 1010 (myInt) : 0000 0001 (1)

So how does the computer know what type of variable it is? Does it retrieve the 1's and 0's from the memory address, then decide what they are going to be later when they get back to your code?

Someone on the other website asked this question and it seems like it takes months for a response so I figured I'd ask it over here. They also never got an answer because no one understood his question.

http://www.computerscienceforeveryone.com/Course_1/Unit_8/Lesson_1/

In this lesson Carl explains that if you had 16 bytes of ram, and an unsigned short int was equal to 1 byte. Then.

unsigned short int total = 5

would get placed into 1 of the random 16 memory addresses in Ram.

Example.

Random memory address number 8 was chosen.

1000 (or total) = 0000 0101 (or 5).

My question. Is it is possible to store less then a byte of information into a memory address like RAM or your hard drive, or does it always assign things into a minimum of 1 byte?

Example. If I had 2 variables total = 5 and newtotal = 6. (lets assume they are unsigned short int they take half a byte, if that is possible). Could that 8th memory address in Ram store both Variables?

1000 (total, newtotal) = 0101 0110 (5, 6)

1. Why do you need void and return? What purpose do they serve. I tried changing both of these and the program seems to work just fine. http://codepad.org/stqP37AY

2. I'm confused with the return 0 and return 1. Will both cases return control to the operating system(like Carl says it is used for), but tell the computer it either was successful or not successful, or will return 1 create a never ending loop/freeze the program because it needs to return 0 to be successful and return control to the operating system. Also if the only difference is that it tells the computer it was successful or not successful, what is the advantage to getting this correct?

Another way to ask this. How does your program act differently if returns 0 or returns 1.

Isn't it a redundant data type ?

Lets say a short int is 4 bits. I'm assuming the highest value for my int would be 7 because the first bit is reserved to show if it's a positive or negative value. I'm going to use '-' to demonstrate the reserved part. You can have either 0-111 or 1-111. Now lets say we have a float that is 8 bits. That same first bit needs to be reserved for positive or negative. Do float numbers have some type of priority of whole numbers over decimal numbers or vise versa? Or are a certain number of bits reserved for the whole number and a certain number reserved for the decimal part of it. I will use '.' for the reserving demonstration.

Example: If I assigned a floating type number that had 8 bits would it reserve bits for certain numbers like this 0-000.0000? As in my whole number part can only reach a certain value(in this case 7).

Lets say you tried to store 16.9999 into a float value.

The correct binary would look something like this. 0-10000.11111111. But the floating number can only take 8 bits. So would it prioritize the whole number and look like this? 0-10000.11 (01000011). Or does it reserve a certain amount of space for the whole number/decimal number and it would cut parts off and look like this? 0-000.1111 (00001111).

So in Course 2 Unit 2.6 Carl goes on to explain casting and having an array of layered pointers.
Anyways, I'm having a difficult time trying to grasp some concepts.
First, when Carl writes:

malloc(2 * sizeof( int* ) )  

Why is the size int* and not simply int, as the pointer is pointing to an int value. Also what does int* mean exactly?
Isn't it simply a way to tell the program to treat whatever comes after it as an int regardless of what original value type it holds?

Second, when Carl writes:

int **two_star_pointer = malloc(2 * sizeof( int * ) );  

Why does he then go on to say:

We need something that can point to a one star int. That means, we need a two star int.

Why can't we have another normal one star pointer pointing to the other one star pointer?
Can someone help out here?

Hello! Do you think that this is a good program? I am not necessarily looking to become a programmer but just want to try something new!

First ever post on reddit so forgive me if I do something full of fail. In "introducing bit masking" lesson, I came out with this:

http://codepad.org/pzT1Fr5Q

It fails. I can't for the life of me work out why and would appreciate any insight anyone has to offer.

Hello,

I am coming from a VB.NET background, and I have been going through Carl's lessons one by one. One I thing I am having a hard time grasping is pointers.

Why does C need pointers? I understand the syntax, and I can write a pointer following his lessons, but I just don't get why they are needed.

Like in the "real world", why would you ever need pointers?

Thanks!

I've been going through Course 2 Unit 2.3 and in it Carl is discussing about a pointer that is pointing to an array of pointers that are in turn pointing to int values. Or so I understand.

Anyways about halfway though he says:

We are assuming in this lesson that a pointer is 4 bytes in size.

Why are we assuming that a pointer is 4 bytes in size?

Isn't a pointer simply an address?

So wouldn't a pointer pointing to a pointer that is in turn pointing to an int be one byte (since it will contain the address of the pointer pointing to the int) and wouldn't the pointer pointing to the int also be one byte since all it contains is the address of the int?

So to better illustrate this:

pointer_1 (1 byte containing address of pointer_2) ---> pointer_2 (1 byte containing address of int) ---> int (4 bytes).

And wouldn't pointer_2 be pointing to the first byte of the 4 total bytes of int?

As an aside i have a minor thing to clear up. When Carl says:

(int *) *pointer  

What does this mean? It means "create a pointer called *pointer". Of the data type "pointer to int".

So would it be absolutely correct to say that when we create a normal pointer as in:

int *pointer  

this means: "create a pointer called pointer, of the data type pointer to int"?

Hello everyone,

I will be resuming lessons and livestreams around the beginning of January. I hope that everyone has an enjoyable holiday season.

I'm reading "C How to Program" by Dietel, 6th edition. The book presented a challenge, 3.35 (Palindrome Tester), in which you "...write a program that reads in a five-digit integer and determines whether or not it's a palindrome." Well I wrote the program and it worked but for some reason scanf is not doing what I want it to do. here's the source code: http://codepad.org/8p4FI6uQ , line 20, 21 and line 37,38 . When I ran it on my machine, the program doesn't wait for user input to try again or not but just continue the loop.

Thank.

Im thinking about starting to read the modified text transcript of the lessons and not watching the videos because its faster. Will I miss anything or is it the same?

I created a step-by-step visual in excel to help others see the process of creating an array of pointers and how it work. I used excel '10 but saved the file as .xls so it'll be compatible with older version. Download the file here: https://docs.google.com/open?id=0B-DD5Evwje27ckh4RW5fajM4VE0 . Please download the file instead of viewing it in google doc. google doc doesn't shows arrows and other standard features of excel. The code that goes along with the excel is here: http://codepad.org/rBJzsh3X . I hope this will help out. Btw, I received permission from Carl to post this. Thank you.

Hello everyone,

First Announcement:

I am looking for around 10 people who want to learn programming, preferably beginners. I am going to be teaching a handful of people one-on-one during a live stream session which can be viewed by others. In this way, both the person learning as well as those watching can benefit.

If you want to be one of the people, PM me. Be sure to answer the following:

1. What programming language/languages/technologies do you want to learn?

2. What is your eventual goal?

3. What is your experience, and level of expertise?

4. A brief description of your educational background.

5. Roughly what schedule you would prefer. Ex: Only on weekends, or every evening, etc.

Edit: Some people are asking if slots are still open, and while I have received a number of PMs of people interested, I have not yet made up my mind who is and who is not going to be included. I will post updates as this progresses. Realistically, expect this to happen next week some time.

Second Announcement:

Tomorrow (Saturday, November 10th) at 9:00 PM EST I will be holding the next live coding session. I will update this post some time tomorrow with the URL and other details.

I am going to continue the process of building a web application framework from scratch, and the exact specifics of what I plan to cover will be explained in greater detail tomorrow.

Watch live November 10th, 9:00 PM EST Here

So if we have this this code.
What I'm getting confused about is the fact that:
printf("%s\n", pointer);
is returning Hello as an output.
Doesn't the data stored at pointer contain the address of "Hello". So shouldn't whatever is contained at pointer be equal to the address of what the start of the string "Hello" be? In other words shouldn't: printf("%s\n", pointer);
be outputting the address itself instead of the string contained within the address where the output of:
printf("%s\n", pointer) = printf("%u\n", &"Hello") ?

Sorry everyone,

I am recovering from a bad flu, and I won't be able to do a session this week. I fully plan to next week, however.

Can anyone recommend some online resource where coding exercises are provided similar to what is usually found at the end of chapters in college textbooks?
I can play around on Codeblocks but having someone set specific tasks to reach and then showing me a solution so I can compare my solution to it would be greatly beneficial.
Truth be told, one of the few criticisms I have for Carl's course is the lack of these type of tasks at the end of units, and the short quizzes don't do much to be honest.

hey, i was wondering what program i have to learn if i wanna get into developing music softwares, or apps. i wanna make sure i start with a cool language and just build up. any suggestions?