Simple hello world program and explanation

HELLO WORLD PROGRAM AND EXPLANATION
• Hello world program

# include<iostream.h> 
#include<conio.h>
// pre-processor directives ,header files 
        Void main ()
// main () is where program execution start
          {
                Clrscr ();
//its clear output of the previous  program.
              Cout<<”HELLO WORLD”;
       // prints hello world .
              Getch();
       //its hold the output screen of the program.
                      }

                       OutPut
                HELLO WORLD

Explanation

Above program is the simple c++ program  which prints “HELLO WORLD”.
• Header files
Header file is the definition of all input and output function  like cin>> ,cout<<; ,getch();
1. #include<iostream.h>
Iostream stand for input output stream .cin>> cout<< whenever these functions are invoked program there definition taken from this  file by complier
2. #include<conio.h>
Conio stand for Console  input output .Commanly used function of conio.h Clrscr(); getch();
• Void main ()
Void main(); is the starting point  of the program when program complied the compiler search for main () then after remained program is compiled.
• Clrscr();
Its working is written in conio.h header file .This function clear output screen of previous program.
• Cout<<
Its definition in iostream.h header file .its used for print the written text  in double quotes  “HELLO WORLD “
Cout<<” HELLO WORLD “;
• Cin>>
Its definition in iostream.h and it accepts the input given by the user
 For eg.
            Void main ()
              {
                       Int a;
                         Cin>>a;
               }
• Getch();
Getch(); is used to hold the output screen until you don’t press any key.
• Comments
Comments are the text written by the programmer for programmer  to understand cod
Comments are tow type

Single-line comment 
// This is example of single line comment.


Multiple line comment
/*
This is  example of multiple line comment
*/