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:
Img

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:

Img

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