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Java Scanner hasNextDouble() Method with Example

Scanner Class hasNextDouble() method: Here, we are going to learn about the hasNextDouble() method of Scanner Class with its syntax and example.
Submitted by Preeti Jain, on February 18, 2020

Scanner Class hasNextDouble() method

• hasNextDouble() method is available in java.util package.
• hasNextDouble() method is used to check whether this Scanner's next input can be manipulated as a double input or not.
• hasNextDouble() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• hasNextDouble() method may throw an exception at the time of checking double value.
  IllegalStateException: This exception may throw when this Scanner is not opened.

Syntax:

    public boolean hasNextDouble();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is boolean, it returns true when this Scanner next token is a valid double value otherwise it returns false.

Example:

// Java program to demonstrate the example 
// of boolean hasNextDouble() method of Scanner 

import java.util.*;

public class HasNextDoubleOfScanner {
    public static void main(String[] args) {
        String str = "Hi, [IncludeHelp] + 10.0 true ";

        // Instantiates a Scanner object with
        // the given string str
        Scanner sc = new Scanner(str);

        //Display str
        System.out.println("sc.nextLine(): " + sc.nextLine());

        // By using hasNextDouble() method is
        // to check whether this Scanner next token
        // contain valid double or not
        boolean status = sc.hasNextDouble();
        System.out.println("sc.hasNextDouble(): " + sc.hasNextDouble());

        // By using close() method is to 
        // close the Scanner object
        sc.close();
    }
}

Output

sc.nextLine(): Hi, [IncludeHelp] + 10.0 true 
sc.hasNextDouble(): false