Introduction to C/C++ Tutorial Part 1



C for beginners, not C++.

This tutorial (or article) is designed for those who want to learn C++ but find a great difficulty in learning it. I also had the same experience when I tried to learn C++, but then, I discovered something that causes the learning gets very difficult. I'll show you that C/C++ is an easy language.

I'll assume that you are beginners to C/C++ because you're reading this. I'll ask you something, what is the difference between C and C++? You probably don't know it. At first, I thought the difference was that C was old, C++ was new. If you think the same way like I did, you're wrong. That's not the difference, there's something else--more important. That what makes the language C++ gets so hard. You will always find trouble in learning C++ unless you understand the difference. Let's take a look at our favorite/boring/hard/confusing "Hello World" program written in C++.

For those who haven't seen this code before, welcome to the wonder of confusion. I'm sure you get really confused looking that code. That code will print a text "Hello World" on the screen. For those you have seen the code and still confused with C++, you will recall that confusion. Let's ask, what does the symbol << actually mean? If we consult our trusty Help manual, it will give you something like this: "bitwise shift operation." Hmm...and what is that supposed to mean? Well, honesty, it's something related to binary computation, pretty much the same like + and -, only that it performs in binary. You're asking, do we really need those stuff if we want to print just a "Hello World" on screen? No. The symbol << in the above code is overloaded by the object cout. The object cout uses symbol << to print the "Hello World." Wait. Overload? Object? Yes, overload, object. Don't get it? Of course, those terms are used when you learn about classes which is unique to C++. Classes are the actual things that differ C++ from C, and those are advanced. I never understand why they use such thing to teach beginners. cout is definitely not for beginners, especially that symbol << that initializes the confusion. At the first time I looked at that symbol I was like "Wow, that's so weird." And I looked at another symbol: >> used by cin, I got confused even more, "Do I have to do this in C++? It doesn't make any sense." It doesn't make sense because C++ uses this:
cin >> a_variable;

when they want to get input from user and put it into a_variable. They don't use the popular equal sign operator like other languages. If you know Pascal or BASIC, you might be like "What the...." You don't understand what it actually does because of the symbol << and >>, then you give up learning and say "C++ is hard." I'm telling you, there's nothing special with C/C++. They're languages, just like Pascal and BASIC, and are learnable. Books and tutorials out there do not give you an easy way to learn it. They give you the hard way by using classes and overloaded operators without giving any details about them. They did that because they think that it's the most basic thing they can teach you, while in fact, it's not basic.

So, now do you understand why you couldn't learn C++ before? I hope you do. Let's forget about all those things and start this tutorial. This tutorial will teach you about C (not C++) language. Don't worry, you are not going to learn something obsolete. As I mentioned before, the biggest difference about C and C++ are these things called classes (and some more). For beginners, they are the same. All you learn here is still valid and still used by people. Once you grasp the knowledge of C, you can start learning about classes (C++) and then you can say, "Hey, C++ is easy."



The C program structure.

Before we start, I highly recommend that you have a working C/C++ compiler on your computer. It may be C or C++ compiler, doesn't matter, as long as it works. Without one, all learning process will be useless. Learn how to compile using your compiler so you know that your code works. One more thing, all we are going to program here run under DOS or console. We're not talking about Windows or GUI (Graphical User Interface, such as buttons and dialogboxes) programming here because it's different and much more difficult. So, if everything is ready and you feel ready too, let's get started.

What is the simplest C program? The "Hello World?" Could be, but I'll tell you what the most important thing in C is that you must have in every C program write (that runs under DOS/console mode). Look at the code below:

That is the most important thing I was referring to. However, if you try to compile it, it will compile but does nothing. Why? Because we haven't put anything in the code. What about that main() and those two braces? What are they doing there? Let's talk about them one by one.

The above code must always present in any C program written for DOS/console. The main() in the above code is called the main function. The main function is the function that defines the body of your program. Without one, your code won't compile. You will type your actual program inside this function. But, how do we know that we are typing inside the main function? The two braces do the job. They simply mean BEGIN and END. The open brace ( { ) means BEGIN, and the closing brace ( } ) means END. This illustration shows how they actually works.

So, if we apply the above illustration to our code above, we know that whatever inside the braces belongs to main(). But in our code, we see nothing between the braces, that's why the code does nothing.

Now, let's discuss more about main(). Why are those parentheses sitting there? Can't we just use main instead of main(). As said before, main() is a function, and a function can take arguments or parameters. The parentheses are used to define those arguments even if we don't have any arguments. If we define an argument, the main() will look something like this:
main(argument)

Since we don't have any arguments, we define nothing between the parentheses. But what about if we do? What happens? If you ever tried to run a program in DOS or from the console, sometimes you are asked to specify some special commands like this:

/mode, /open:sample.txt, and /scan are the arguments of the main function of program.exe. We define arguments for the main function when we want to make our program to accept some commands like the above example. These arguments are called command-line arguments. For now, we don't talk about it, so just leave it blank.

Now, let's complicate the code a little bit by adding one more word.