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:

 

·       Standard Libraries Section

·       Main Function Section

·       Function Body Section

 

For example, let’s look at the implementation of the Hello World program

 

#include <iostream>

using namespace std;

 

int main() {

  cout << "Hello World!" << endl;

  return 0;

}

 

 

Standard libraries 

#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 

 

Main Function Section

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