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C++

Hello World! - Your First C++ Program

What is C++?

C++ is a general purpose programming language which has been used since the 1990's
It was designed by Bjarne Stroustrup under with the name "C with classes".
It is a version of C that includes Object-Oriented elements, including classes and functions.
It is considered one of the biggest programming languages, as you can see in the following image: source: Github

Your First Program in C++

#include <iostream>
using namespace std;
int main()
{
    cout << "Hello World" << endl;
    return 0;
}

The Output of this program will simply be :

Hello World!

Now, let's break down the code:

Lines 1 and 2

#include <iostream>
using namespace std;

The first line tells the computer to use the "iostream" header file for this specific program . A header file is a seperate file with prewritten C++ code. There are many other header files which are requireed for a specific program to run properly. Some of them are : math , vector and string. Header files are generally represented by a ".h" extension (you don't need to add .h when including C++ standard library files)
iostream stands for input-output stream . The "iostream" file contains code for allowing the computer to take input and generate an output, using the C++ language.
The second line tells the computer to use the standard namespace which includes features of standard C++. You could write this program without this line, but you'd have to use std::cout instead of cout and std::endl instead of endl on line 4. It makes the code more readable and our lives as programmers easier.

Line 3 and 4

int main()
{

C++ starts execution of a program from the -main function- int main() . During execution , the computer starts running the code from every line from {(opening bracket) till }(closing bracket) NOTE : Every function starts with an opening curly brace "{" and ends with a closing curly brace "}".
Line 4 indicates the start of the main() function.

Lines 5, 6 & 7

    cout << "Hello World" << endl;
    return 0;
}

The word cout in C++ is used to output.
It is followed by << , the insertion operator .
Whatever is in the double quotes "" is printed . Certain special characters have a different syntax for print statements
Now to print any other kind of data , you have to add << .

Challenge: Try to change Hello World to any other sentence or word(s). What will be the output ?

endl is a reserved word when using the C++ language to end this line and go to the next line during output . - cout stands for "console output"
Finally, finish the command with a semicolon ;.

NOTE : Every command except the main function definition and the #include directive needs to be ended by the semicolon. Without a ";" , you may encounter an error.

return 0; safely terminates the current function i.e. 'main()' in this case and since no function follows after 'main()' the program is terminated.
Don't forget to tell the computer that this is end of the main() function. To do this , you add the closing curly brace "}". You will encounter an error before program execution if you do not include the } .

The code should look something like this:

Programmers use a Hello World program (like this one) as a ritual on using a new programming language. It is a symbol of good luck.
You have finished coding your first C++ program and have understood most of the code you have written/typed. CONGRATULATIONS!

Good Luck to all of you and happy coding! :)

Happy Coding ! :)

Feel free to ask any questions on FreeCodeCamp's GitHub page or FreeCodeCamp's Forum.

Try it yourself ! :)

You may need some software to write and execute C++ code. I recommend using CodeBlocks. There's a download link below :

Download Link : Download Here

Click the link with the GNU/GCC compiler for windows. This will not require an additional installation

Other alternatives could be visual studio, using a compiler or an online IDE such as Cloud9 or repl.it

Link #2 for Mac : Download for Mac #2 here

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