# Java Comments and Type Casting

**Hey all!** Hope you have understood the data types and variables in the previous article. Now it's time to move a step ahead. Today in this article we will cover Comments and Type Casting. So let's start with it. First, we will cover Java comments.

**What are Comments? **
For a random person, comments are used to pass in lecture, But for programmers, comments are used to describe the purpose of a written code statement. In java, comments are given in the following ways:

For one-line comment **'//' ** is used.

```
int i=1;   //This is one line comment
``` 
For multiline comment  `/*..........*/ ` is used.

```
int i=1; 
/* This is 
multiline comment
 */
``` 
That's all with comments. Now let's start with Type Casting.

**What is Type Casting?**
Type Casting is used to convert one data type to another data type. Eg: int to double.

Type Casting is categorized into two types:-

- **Widening Casting**: This casting is done automatically by the Java compiler. In this, a smaller data type is converted to a larger data type size. The following flow shows how casting is done.

`byte`--> `short `--> `char` --> `int` --> `long` --> `float` --> `double`

-** Narrowing Casting**: This casting is done manually. In this, a larger data type is converted to a smaller data type size. The following flow shows how casting is done.

`double` --> `float` --> `long` --> `int` --> `char` --> `short` --> `byte`

If you are getting confused, then don't worry below codes will help you to understand it properly.


- **Widening Casting**:
```
public class Main {
  public static void main(String[] args) {

         int intNumber=10;
        System.out.println(intNumber);       // Output:  10

        double doubleNumber = intNumber;   //Typecasting (Widening) Automatic casting from int to double
        System.out.println(doubleNumber);   // Output: 10.0

  }
}
``` 

- **Narrow Casting**:

```
public class Main {
  public static void main(String[] args) {

        double doubleNumber = 12.3d;   // Output:  12.3
        System.out.println(doubleNumber);

        int intNumber= (int) doubleNumber;  // Typecasting(Narrow) Manually : double to int
        System.out.println(intNumber);     // Output:  12
    
  }
}
``` 

> Tip: In Narrow Casting, you have to type manually the data type in parentheses '( )' in front of the value or variable. In the above code, it is clearly mentioned: int intNumber= (int) doubleNumber;
This converts a double data type number to an integer number.

Hope you have understood today's topic. Thanks for your time. Happy Programming!