Comparitive Study of Hello World Program in C , C++ and Java

This tutorial describes the structure of programs in C , C++ and Java programming languages through "Hello World!" program example. This will help the new programmers a lot to understand the syntax of programs in these programming languages through this comparitive study.

As you know, The Turbo C++ or Dev C++ etc. compilers can be used for coding C & C++ Programs. We save the programs as name.c and name.cpp for C and C++ programs respectively.

Netbeans IDE or Eclipse platforms can be used for making applications in Java. Both provides a good environment for developing java applications.

The ' Hello World! ' program simply prints a line displaying  Hello World!  as output.

Let`s get the comparative study through "Hello World!" Program Example :

---

Hello World! Program in C :

---

#include<stdio.h>

#include<conio.h>

main()

{

    printf("Hello World!");      /*This is a statement */ 

    getch();

}

• The inclusion of the statements #include<stdio.h> and #include<conio.h> at the beginning uses the input/output library functions.These stands for standard input output and console input output respectively.The lines beginning with # are the directives for the pre-processor.

• We included #include<conio.h> for the getch() which stands for getcharacter.

Note : If we use return 0 instead of getch() , there is no need to include #include<conio.h> library function.

• Always remember , there is only one main() function in every C Program.The opening brace '{' marks the beginning of the main function and closing brace '}' indicates the ending of the function.

• The lines between these /*...............*/ are comment lines.Comments have no effect on the execution time.

• Every statement should end with a semicolon ( ; ) mark.

---

Hello World! Program in C++ :

---

#include<iostream>
#include<conio.h>
using namespace std;

main()
{
    cout<<"Hello World!";            // This is a statement.
getch();
}

• #include <iostream> includes the declaration of standard input-output library in C++.

• All the elements of standard C++ library are declared within a namespace,the namespace with the name std is used in C++ programs.

• The execution of the program starts from the main() function in C++. ' ( ) ' is the pair of parenthesis.

• cout is named for the standard output stream in C++. cout is declared in iostream standard file.

• We included #include<conio.h> for the getch() , If we use return 0 instead of getch() , there is no need to include #include<conio.h> library function.

• Every statement should end with a semicolon ( ; ) mark.

• The lines after the ' //.............. ' are comment lines. // is used for comments in C++.   /*...............*/  can also be used. 

Note : //............... works only for single line comment while /*...............*/ are used for block comments means a no. of lines will be considered as comments between /*...............*/ .Comments have no effect on the execution time.

---

Hello World! Program in Java :

---

/** This is a simple application in java to 

* print Hello World! message */

public class Hello 
{
    public static void main (String[] args) 
    {
        System.out.println("Hello World!");
    }
}

• Hello is the class_name in this program. i.e. class class_name is the declaration.

• The main method is similar to the main function in C and C++.It is the main entry in the program where the execution of the program begins.

                public static void main(String[] args)

       
The main method accepts a single argument. i.e. an array of elements of  type String

      
 The modifiers public and static can be in any order. i.e. public static or static public.

System.out.println("Hello World!"); This uses the System class from the core library to print the message to standard output.

/*......block comment......*/ ,  //.....line comment...... and /**.....document comments.....*/
 all are used in Java Programs.Comments have no effect on execution time.

Every statement should end with a semicolon ( ; ) mark.

Here, I tried to explain a comparative study using Hello World! program so that you can easily understand the basic syntax ( structure of the program ) of the program in C , C++ and Java.

[Read] C vs C++ vs Java

Enjoy the Programming.

Have Fun!