Comments and Expression

Comments

Comments in programming languages are the values ignore by the compiler. Usually comments are used in the programming language for documentation. Suppose you write the code for the some specific piece of work and use in your current project, after 3 months you need that same function again you could remember that code is somewhere but you need to read all the logics and identified the desired code. If you have code in this code you can take that code from that place.

There are two type of comments

• one line comments
• multiline comments

Let see how to implements the comments in Java code
Single line comments

 // This is single line comments  
 public class Main {  
  // main method it is entry point for the java program  
   public static void main(String []args){  
    // Display the output on the console  
    System.out.println("Hello World");  
  }  
 }  

Multiline comments

 /* This is multiline comments  
   This class will use for the main method  
 */  
 public class Main {  
  /*  
    main method it is entry point for the java program  
    what you want to write here!!!  
  */  
   public static void main(String []args){  
    // Display the output on the console  
    System.out.println("Hello World");  
  }  
 }  

Expressions

In this lesson we will learn about the expressions in Java. Expression is combination of the values, variables, constants and operators. Let say x is a variables and has a value 4. If we say

y = x + 3

is expression.

 public class MyClass {  
   public static void main(String []args){  
    // expression  
    int x = 4;  
    // expression  
    int y = 7;  
    // expression  
    int answer = x + y;  
    // output  
    System.out.println(answer);  
  }  
 }  

 /*  
  This is expression example  
 */   
 public class MyClass {   
   public static void main(String []args){   
   // This is string value   
   String x = "Hello";   
   // expression   
   String y = "World";   
   // expression   
   String answer = x + y;   
   // output   
   System.out.println(answer);   
  }   
  }