I want to learn to C - Page 3

Objects and object-oriented programming languages were something designed to make human design of programs simpler. The entire idea behind an Object is that you group similar properties and functions of a "real-life" object into one cute name.

Here's an example to give you a better idea. Suppose you were designing a video game and inside that video game there are tanks. We can even take the Seige Tank is starcraft as a concrete example. If were to think about the important PROPERTIES of a tank we could make a short list, something like this:

- Armor
- Damage
- Health
- Speed

And if we were to think of some important functions or actions of a tank we could come up with something like this:

- Attack
- Seige Mode
- Stop
- Move

Now I can create an "object" that groups all these properties together to make it easy for myself. I could say:

myTank.Armor = 3; <- This would change the armor value of the tank to 3
myTank.Damage = 10000; <- Holy crap that's STRONG!!!

C lacks the ability to create objects directly. However, in can still be done pretty similarly to most high-level langauages through the use of structures. You will learn about those eventually.

As you may imagine, inside your program you will be creating a bunch of variables, objects, strings, and all sorts of stuff. Well, who is keeping track of all that stuff? When should stuff be destroyed and when should it be kept?

The answer to this question depends on what language you are programming in. Most really high level languages like java, C# and many others have what is called Garbage Collection and Automated Memory Management.

Garbage Collection and automated memory management is exactly what it sounds like. Your program will cycle through all the stuff you've made and delete things that it thinks you will no longer ever use. Most of the time this works pretty well, meaning you can program-and-go and not have to think about problems with memory space running out or using something you shouldn't be using.

C does not gave garbage collection. You will be doing everything manually, so you must keep track of all variables, pointers, and memory that you use. This may sound daunting, and sometimes it can be, but unless you're solo making software to manage an entire airplane that spans over a million lines of code it probably would not bother you too much.

Pointers? What the hell is a pointer, anyway? A pointer is exactly what it sounds like. It's a VARIABLE that points to something. More technically, pointers point to addresses of memory inside a computer. Snooze. Sounds simple, right?

Apparently it's not. Pointers can be too compliated for some programmers, which is why languages like java and C# have allegidly gotten rid of them. I say allegidly because pointers are such a fundamental part of modern day computers that there really is so escpating them. Really high level languages like java HIDE all the pointer operations going on the background to make programming more trivial.

C does not. You will be dealing with pointers DIRECTLY, and often times even things you think are simple library functions will use pointers. To give a crude example, say you wanted to copy a string. Well. cplusplus.com has a great resource that lays out the common C libraries very nicely for you. You will be using these libraries very often, so keep this link handy!
Link is: http://www.cplusplus.com/reference/clibrary/

Let's take a look at strcpy() (Short for String Copy) Link is: http://www.cplusplus.com/reference/clibrary/cstring/strcpy/
" char * strcpy ( char * destination, const char * source ) "
This part is the meat of the function. Almost every time you see an ASTERISK (*) in a program in C, it's a pointer. So this function takes in two pointers and even returns a pointer! Just to copy a string!!

The truth about the matter is that pointers require getting used to, but living without them is impossible. They are wonderful and really amazing tools in a programming language.

I realize this probably doesn't matter for you, but higher level languages are generally more secure. That's because majority of low level control is hidden from you. You must realize that your program will be grossly insecure in C. So if you plan on writing an FTP server where people will be submitting personal information, I'd look into learning about how to program securely.

#include <stdio.h>

int main(int argc, char *argv[])
{
printf("Hello World!! \n");
system("PAUSE");
return 0;
}

C:\Program Files (x86)\AMD APP\bin\x86_64;C:\Program Files (x86)\AMD APP\bin\x86;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\ATI Technologies\ATI.ACE\Core-Static;C:\Dev-Cpp\bin

WARNING: DO NOT COPY MINE. JUST AN EXAMPLE.

"cd" changes your directory.
Example 1: cd C:\Windows
Example 2: cd Desktop

"dir" lists all files in the directory.
Example: dir

Use these to navigate to your desktop.