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  1. #1
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    C++ Tutorial Chapters 1 & 2

    Okay here are two chapters I wrote for my site a while ago. I thought I'd post them here. There might be some technical errors, so sorry.

    C++ Programming (Chapter One) by Jethro

    Topic: Programming

    http://jethrojones.hyperlinx.cz


    -------------------------------



    This tutorial is about basic programming with C++. Very basic.

    If you are a newbie however, you many find this tutorial quite useful...

    We cover basics like variables, functions, compilers,

    headers, operators...etc



    C++ (pronounced "see-plus-plus") is an extended version of the

    C language which was developed in Bell Labs in 1978. In the

    early 80's, C++ was created as an object-orientated language.

    Without going into too much detail on the history of C++, I'll

    tell you this: C++ is the language which most software developers favour,

    because of its power, ease-of-use and its acceptance

    on most systems, such as Windows and *NIX.



    To make a C++ program you will need a compiler. I use Dev-C++ for

    Windows (http://www.bloodshed.net) but there are good ones such as

    Borland C++ Builder 5.5 (http://www.borland.com) and for UNIX, the

    famous GCC compiler is the best. This comes with a lot of UNIX systems

    like Red Hat Linux, I believe.



    Before the code can be executed, it must be linked to other

    pieces of code (e.g. included libraries) used by the program. The

    compiled & linked program is called an executable file. Finally,

    the program is executed by the system. The compiler does this.

    Compilers takes your typed source

    code and translates it into machine code (1s and 0s).



    Here is an example program:



    ************ helloworld.cpp ************



    Code:
     /* This is a comment
    
        Hello World program
    
        Written by Jethro */
    
     
    
     #include <iostream.h>
    
     
    
     int main()
    
     {
    
        cout << "Hello World" << endl;    // First statement
    
        return 0;                         // Second statement
    
     }

    *****************************************



    Okay, time to go through this line-by-line...





    *****************************

    /* This is a comment

    Hello World program

    Written by Jethro */ = This is a comment. There are two types

    of comments. Comments which run over a few lines (multiline) or

    single-line comments. This is an example of a multi-line comment.

    Everything between "/*" and "*/" gets ignored by the program itself.

    Comments are good for people who read your code, so they know what

    everything does so they can fix/debug it easily.

    *****************************

    #include <iostream.h> = This tells the compiler that the "iostream.h"

    library file is needed and should be included when compiling the code. A

    library is a collection of program code that can be included (and used) in

    a program to perform a variety of tasks. "iostream.h" is a library

    (or "header") that performs certain input and output functions. You can get

    these library files (if for some strange reason they didn't come with your

    compiler) at loads of different websites like http://code.box.sk.

    *****************************

    int main() = Okay, this is fairly complicated but bare with

    me. "int main()" is a function header. "main()" is the function name. A

    function is a collection of statements. A function header includes the return

    type of the function (what it returns to the place it was called when it exits)

    and the function name, in this case "main". This function returns an INTeger

    through the line "return 0", but more on integers and the RETURN statement later.

    So all the functions that have an integer as the return type return integers.

    All the statements in a function are enclosed in curly brackets "{" and "}".

    This means that everything between the open bracket "{" and the closed bracket

    "}" are part of that function. I hope I didn't make that sound too complicated.

    You'll get it eventually, even if you don't understand it now.

    Note: For a function to be executed it needs to be called. You can call a

    function from anywhere, just by entering its name, like "askName()", except

    for the main() function. This is called automatically when the program is

    executed. This is why we don't call it. main() funcions usually return an integer.

    *****************************

    cout << "Hello World" << endl; = This prints "Hello World" to the screen.

    "Hello World" is a string of text (in programming, there's no other kind of

    string, other than a text string).

    This line is an example of a stream. A stream is an input/output

    device. "cout" (pronounced "see-out") is the Console OUTput stream. "iostream.h"

    needs to be INCLUDEd when we use streams. First we send "Hello World". We send it

    using an operator. The "<<" operator. This basically means, send the string to the

    cout stream. Then we also send "endl" (this is optional). endl means END Line, so

    if we send some

    sort text to cout, it will appear on a new line. All statements are ended with a

    semi-colon ";".

    ****************************

    // The first statement

    // The second statement = These are both examples of one-line comments.

    ****************************

    return 0; = This returns the integer 0 from where it was called. In the

    case of the main() function, this just means it exits fine. The main() function

    should always return a 0. More of the return command later.

    *****************************



    And that is helloworld.cpp explained. Just compile that and view it.





    Variables.



    Variables are pieces of information stored on the memory. There are three parts

    to a variable. Its name, type and value. Its name is just what we call it. Its

    value is the information it holds. This can be an integer, a decimal, a string...etc.

    It's type is defined in accordance to the information it is going to hold:



    int = -32,768 to 32,767

    long int = -2,147,483,648 to 2,147,483,647

    float = 1.2 x 10^-38 to 3.4 x 10^38

    double = 2.2 x 10^-308 to 1.8 x 10^308

    char = 256 character values



    Here is an example program which shows this:



    ************** numbers.cpp ***************

    Code:
    /*  To show variables in action
    
        Numbers program
    
        Written by Jethro         */
    
    #include <iostream.h>
    
    #include <stdlib.h>
    
     
    
    int main ()
    
    {
    
      int num1;
    
      int num2;
    
      cout << "To show variables" << endl;
    
      cout << "Please enter a number: ";
    
      cin >> num1;                                   // User input #1
    
      cout << "\nPlease enter another number: ";
    
      cin >> num2;                                   // User input #2
    
      cout << num1 << " + " << num2 << " = " << num1+num2 << endl;    // Add
    
      cout << num1 << " - " << num2 << " = " << num1-num2 << endl;    // Subtract
    
      system("PAUSE");
    
      return 0;
    
    }
    ******************************************



    New stuff:

    *********************************

    #include <stdlib.h> = This is another example of using one of the

    countless header files available in C++. We need to include "stdlib.h"

    because we use the SYSTEM() function to interface with MS-DOS.

    *********************************

    int num1; and int num2; = Here we declare two integer-type variables.

    We call them (originally enough "num1" and "num2". But you can call them

    "drag" and "weed" if you want, it doesn't matter. Just remember that C++ is

    CaSe SeNSiTiVe, so num1 is not the same as Num1, nUm1 or even nuM1! We don't

    give them values, we can assign them values later... Anyway, as long as you

    know that that means they are integers, it's okay.

    ********************************

    cin >> num1; = "cin" (pronounced "see-in") is another example of a stream,

    courtesy of "iostream.h" again. This means that everyhing the user types, up

    to the carriage return (aka. "Enter"), will be included into the variable "num1".

    Notice the way we use ">>" to symbolise that the information is going from

    "cin" to "num1", not vica versa, as is in the "cout" stream. We did not use

    "endl" on the previous line, because we wanted the user to type the number

    right after "Please enter a number: ".

    *******************************

    cout << "\nPlease enter another number: "; = Your probably wondering why

    I put '\n' there. Well, it's simple. \n means go to a new line. Similar to

    endl. The following line:

    'cout << "\n\n\nThree lines down";' would print out the words "Three lines

    down", three new lines down.

    *******************************

    "num1+num2" and "num1-num2" = This is the use of operators. num1+num2

    returns the value of num1 added to num2 and num1-num2 gives the value of num2

    subtracted from num1. This does nothing to the actual value of the variable

    however.

    + = Addition

    - = Subtraction

    * = Multiplication

    / = Division

    *******************************

    system("PAUSE") = The system() function, courtesy of "stdlib.h",

    lets you run an MS-DOS command. If you have read any of tutorials (I have

    written a few) on MS-DOS, you will know that this creates the prompt "Press

    any key to continue..." and will not continue executing the program until

    the user has pressed a key.

    *******************************



    And that's numbers.cpp...



    I think that's enough for Chapter One. In Chapter Two I will talk about

    functions, conditional statements, loops and whatever else I think of.



    If Chapter Two hasn't been written yet, check back in a few days.



    **************** EOF ***************

  2. #2
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    C++ Programming (Chapter Two) by Jethro

    Topic: Programming

    http://jethrojones.hyperlinx.cz


    -------------------------------



    This is the second chapter in my current series of Computer Programming

    with C++. If you haven't read Chapter One, then read it now. It might

    shed some light on some of the techniques used in the section. In this

    section we are going to cover:



    Index:

    o Conditional Statements (IF...ELSE)

    o Loops (FOR...WHILE)



    Here we go!



    ************** checkage.cpp ************



    Code:
    /* This program checks
    
       what age you are! !!!WOW!!!
    
       Written by: Jethro */
    
     
    
    #include <iostream.h>
    
     
    
    void main() {
    
     
    
      int age;
    
      cout << "The amazing age checking program" << endl;
    
      cout << "Enter you age in here please: ";
    
      cin >> age;
    
     
    
      if (age==18) {
    
        cout << "\tYou are just old enough to vote" << endl;
    
      }
    
     
    
      if (age==16) {
    
        cout << "\tYou are just old enough to drink" << endl;
    
      }
    
     
    
      if (age>10) {
    
        cout << "\tYou are older than 10" << endl;
    
      }
    
     
    
      if (age<70) {
    
        cout << "\tYou are younger than 70" << endl;
    
      }
    
     
    
      if (age!=13) {
    
        cout << "\tYou are not 13" << endl;
    
      }
    
     
    
      else {
    
        cout << "\tYou have some kind of crazy age!" << endl;
    
      }
    
     
    
    }

    *****************************************



    Ahh, let's check this stuff out.



    The conditional statement is easy to understand. If you have ever

    learnt a programming language i your life, then you will probably know

    that nearly every language has some sort of a conditional statement. A

    lot of languages (eg. PHP, JavaScript...etc) have this exact kind of

    conditional statement:



    IF (conditional) {

    statements

    }



    The "if" part is pretty easy to understand. If the (conditional) is

    true then the "statements" should be executed. The condition is

    usually in the following form:



    IF (variable==value) {

    do something

    }



    For example. In the checkage.cpp we used many variations of this. The

    first was:



    if (age==18) {

    cout << "\tYou are just old enough to vote" << endl;

    }



    This means that if the age variable is equal to 18 the execute the

    statement:

    'cout << "\tYou are just old enough to vote" << endl;'



    I think that's fairly easy to understand. But what if you want to check

    if it isn't equal to it, or it's bigger than that. Then you use a

    different operator. Here is a list of some of the most common:



    ************************

    Operator - Definition

    ----------------------

    == - Equal To

    != - Not equal to

    < - Smaller than

    > - Bigger than

    <= - Smaller or equal to

    >= - Bigger or equal to

    ************************



    By putting an exclamation mark (!) infront of any of these, turns them

    around. For example age!<6 would be true if "age" wasn't smaller than

    6. But why say this when you can say >?



    When all else fails, use "else". This is used when none of the

    conditional statements are true. Of course, the else statement doesn't

    need a condition.



    ******************* loops.cpp **********************



    Code:
    /* This program shows
    
       examples of the FOR
    
       and WHILE loops
    
       Written by: Jethro */
    
     
    
    #include <iostream.h>
    
     
    
    void main() {
    
     
    
      int i, num1;
    
      for (i=0; i<=10; i++) {
    
        cout << "Saying this for time number: " << i << endl;
    
      }
    
     
    
      while (num1!=5) {
    
        cout << "Please enter the number 5: ";
    
        cin >> num1;
    
      }
    
     
    
      cout << "You got it right!" << endl;
    
    }

    *****************************************************



    More stuff to discuss:



    FOR

    ---

    The loop is really easy as well.



    The FOR statement has a few different things packed into the one

    statement, but it's easy once you get the hang of it.



    Let's examine/dissect it piece by piece:



    for (i=0; i<=10; i++) {

    cout << "Saying this for time number: " << i << endl;

    }



    FOR - This starts off the statement

    i=0 - This defines the "i" variable as being 0

    i<=10 - This makes it so that "i" shouldn't go past 10

    i++ - This increments the "i" variable. Basically this means "i=i+1".

    "i--" is the same as "i=i-1". We add this so that every time the loop

    executes, "i" gets a little bit bigger. If this didn't happen, the

    loop would execute infinitely!



    *******

    Note: If you have read other tutorials on programming with loops you

    probably have seen them use a variable called "i" as well. This is

    because using "i" is an age-old tradition in loops. I don't really

    know the actual reason for this, but I use the i variable because it's

    the first one that comes to mind. You don't have to, of course.

    *******



    With the above loop, the loop will start at 0 and keep executing the

    "cout << ...etc" statement until it reaches 10.



    WHILE

    -----



    The WHILE statement is considerably easy to understand than FOR is.

    Basically, the WHILE loop will keep executing while the conditional

    statement is met. Kind of like a power-crazy "IF" statement. Here is

    the WHILE syntax:

    ********

    WHILE (condition) {

    statement

    }

    ********

    For example:

    **********

    Code:
    int jk = 0;
    
    WHILE (jk!=5) {
    
    cout << "\nJK is 5! Change it: ";
    
    cin >> jk;
    
    }
    **********

    The above loop would keep executing WHILE "jk" is not equal to 5. Of

    course if you use this command and don't give the program the

    opportunity to change it, it will just keep repeating forever and ever

    and ever.



    And that's Chapter Two finished. Pretty easy stuff, isn't it? Chapter

    Three will be out soon!



    ****** EOF ******

  3. #3
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    Thanks, this will help out lots, and get them started.
    [gloworange]Die, or surrender, either way won\'t work.[/gloworange]
    [shadow]HuntX7[/shadow]

  4. #4
    Now, RFC Compliant! Noia's Avatar
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    Could you put these in .DOC's or something...
    I wan't to store a copy on my File-Store....
    - Noia
    With all the subtlety of an artillery barrage / Follow blindly, for the true path is sketchy at best. .:Bring OS X to x86!:.
    Og ingen kan minnast dei linne drag i dronningas andlet den fagre dag Då landet her kvilte i heilag fred og alle hadde kjærleik å elske med.

  5. #5
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    I have the two files in .html format. Wait, I'll attach them...

  6. #6
    Antionline Quitter..Srsly
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    awesome.../me goes off to learn c++
    \"\"A weak mind is like a microscope, which magnifies trifling things but cannot receive great ones.\" — G.K. Chesterton, 19th-century English essayist and poet\"

  7. #7
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    Thanks... I already know it though :P Thanks tho...

  8. #8
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    nice 1 mate cheers
    By the sacred **** of the sacred psychedelic tibetan yeti ....We\'ll smoke the chinese out
    The 20th century pharoes have the slaves demanding work
    http://muaythaiscotland.com/

  9. #9
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    If you wanna know more read a book, try 'Sams Teach Yourself C++ in 21 Days'
    [gloworange]Die, or surrender, either way won\'t work.[/gloworange]
    [shadow]HuntX7[/shadow]

  10. #10
    Antionline Quitter..Srsly
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    hey jethro u must kinda happy IRELAND tied the game against GERMANY...or do u not like soccer?....well anyway i think maybe u should submit ur C++ tutorial to the AO newsletter talk ot MsMittens that would be cool to put in there
    \"\"A weak mind is like a microscope, which magnifies trifling things but cannot receive great ones.\" — G.K. Chesterton, 19th-century English essayist and poet\"

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