Structure of C++ program with simple C++ program

In this article, we will learn about the structure of the C++ program with a simple c++ hello world program.First we will start from the structure of c++ program.

Structure of c++ program

A C++ program is structured in a specific and particular manner. In C++, a program is divided into the following three sections:

1. Standard Libraries Section
2. Main Function Section
3. Function Body Section

Let’s take a example to understood the above three sections.

#include <iostream>
using namespace std;

int main() {
  cout << "Hello World!" << endl;
  return 0;
}

Above the simple hello world c++ program, now we will understand each and every section.

Standard libraries section

#include <iostream>
using namespace std;

• #include is a specific preprocessor command that effectively copies and pastes the entire text of the file, specified between the angle brackets, into the source code.
• The file <iostream>, which is a standard file that should come with the C++ compiler, is short for input-output streams. This command contains code for displaying and getting an input from the user.
• namespace is a prefix that is applied to all the names in a certain set. iostream file defines two names used in this program – cout and endl.
• This code is saying: Use the cout and endl tools from the std toolbox.
• Here cout is used for printing the code where as endl is used for next line.

Main Function Section

int main() {}

• The starting point of all C++ programs is the main function.
• This function is called by the operating system when your program is executed by the computer.
• { signifies the start of a block of code, ​and } signifies the end.

Function body section

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

• The name cout is short for character output and displays whatever is between the << brackets.
• Symbols such as << can also behave like functions and are used with the keyword cout.
• The return keyword tells the program to return a value to the function int main
• After the return statement, execution control returns to the operating system component that launched this program.
• Execution of the code terminates here.