* The first line tells the computer to use the "iostream" header file for this specific program. A header file is a separate file with prewritten C++ code. There are many other header files which are required for a specific program to run properly. For example, math, vector, string, etc. Header files are generally represented by a ".h" extension, when including standard library header files you don't include the ".h" extension.
* The `iostream` header contains the public interface for the input-output stream from the standard library. 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.
* 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)
*`endl` is another symbol from the iostream library which means to **end this line and go to the next line during output** . - _cout stands for "console output"_
* Finally, finish the statement with a semicolon `;`.
**NOTE : Every statement except the main function definition and the #include directive needs to be ended by the semicolon. Without a ";", you may encounter a compiler error.**
* 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 compiler error before program execution if you do not include the **}** .