Java Double toString() example

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In this guide, you will learn about the Double toString() method in Java programming and how to use it with an example.

1. Double toString() Method Overview

Definition:

The toString() method of the Java Double class returns a string representation of the specified double value.

Syntax:

1. String Double.toString(double d) 
2. String doubleValue.toString()

Parameters:

For the static method:

double d: The double value to be converted to a string.

For the instance method:

There are no parameters as the method will return the string representation of the object's value.

Key Points:

- The resulting string will contain one digit in the least significant digit of the integral part and at least one digit in the fractional part.

- This method can handle and represent both regular floating-point numbers and numbers in scientific notation.

- There are two variants: a static method that takes a double as a parameter, and a non-static (instance) method that operates on the instance's value.

2. Double toString() Method Example

public class ToStringExample {
    public static void main(String[] args) {
        // Using static method
        double num = 123.45;
        String strValue = Double.toString(num);
        System.out.println("String representation using static method: " + strValue);

        // Using instance method
        Double doubleInstance = 456.78;
        String instanceStrValue = doubleInstance.toString();
        System.out.println("String representation using instance method: " + instanceStrValue);
    }
}

Output:

String representation using static method: 123.45
String representation using instance method: 456.78

Explanation:

In the provided example, the static toString() method of the Java Double class is used to convert the double value 123.45 into its string representation. 

Next, the non-static (instance) toString() method is demonstrated, where an instance of the Double class holding the value 456.78 is converted to its string representation. Both methods effectively transform a double value into its equivalent string format.