How to Convert Int to Double in Java?

In Java, smaller datatype can be converted to bigger datatype. Here, we will see how to convert int datatype to double datatype.

The int data type is a 32-bit signed two's complement integer. Its value-range lies between - 2,147,483,648 (-2^31) to 2,147,483,647 (2^31 -1).

The double data type is a double-precision 64-bit IEEE 754 floating point. Its range of values is beyond the scope of this discussion, but is specified in the Floating-Point Types, Formats, and Values section of the Java Language Specification.

Let’s deep dive into this article, to know how it can be done by using Java programming language.

To show you some instances

Instance-1

• Suppose the given int datatype is ‘1021’.

• Then it will be converted to double datatype and result will be −

• Double value is: 1021.0

Instance-2

• Suppose the given int datatype is ‘3265’.

• Then it will be converted to double datatype and result will be −

• Double value is: 3265.0

Instance-3

• Suppose the given int datatype is ‘102’.

• Then it will be converted to double datatype and result will be −

• Double value is: 102.0

Algorithm

• Step-1 − Declare the int datatype.

• Step-2 − Convert it into double datatype.

• Convert Implicitly

• Using Double wrapper class

• valueOf() method

• Step-3 − Print the result.

Syntax

valueOf() − In java, valueOf() method converts different types of values like float, byte, int etc into string.

Multiple Approaches

We have provided the solution in different approaches.

• By Using Assignment Operator

• By Using Double Class Constructor

• By Using valueOf() method

Let’s see the program along with its output one by one.

Approach-1: By Using Assignment Operator

In this approach, int will be converted to double by simply assigning the int datatype to double datatype. This is done by compiler implicitly and is known as implicit type casting.

Example

public class Main {
   //main method
   public static void main(String args[] ){
   
      //Declaring int datatype
      int i = 1021;
      // Implicit conversion from int to double data type
      double d = i;
      
      //printing int datatype
      System.out.println("Integer value is: " + i);
		
      //printing double datatype
      System.out.println("Double value is: " + d);
	}
}

Output

Integer value is: 1021
Double value is: 1021.0

Approach-2: By Using Double Class Constructor

In this approach, int value can be passed to the constructor of the Double class to create an object of double type. Double class is a wrapper class used to create objects that can hold single, double type values and contain several methods to deal with double matters.

Example

public class Main {
   //main method
   public static void main(String args[]){
	   
      //Declaring int variable
      int i = 3265;
      
      //int to double datatype conversion using Double wrapper class
      Double d = Double.valueOf(i);
	   
      //printing int datatype
      System.out.println("Integer value is: " + i);
      
      //printing double datatype
      System.out.println("Double value is: " + d);
   }
}

Output

Integer value is: 3265
Double value is: 3265.0

Approach-3: By Using valueOf() Method

In this approach, valueOf() method is used. valueOf() method belongs to Long Wrapper class. It accepts an integer as an argument and returns a double value after the conversion.

Example

public class Main {
   //main method
   public static void main(String[] args){
	   
      //Declaring int datatype
      int i = 100;
		
      //int to double data type conversion using valueOf() method
      Double d = Double.valueOf(i);
	   
      //printing int datatype
      System.out.println("Integer value is: " + i);
		
      //printing double datatype
      System.out.println("Double value is: " + d);
	}
}

Output

Integer value is: 100
Double value is: 100.0

In this article, we explored different approaches to convert int to Double by using Java programming language.