Reading from file double value using Scanner - InputMismatchException?

Question

I tried read from file double values and using Scanner with this aim.

It throws InputMismatchException :

\"input.txt\"  java.util.InputM         


        

Answer 1

• Initialise largest to the first double (after checking the type)

• Use the correct delimiter to parse your input (\n = newline)

  String filename = "input.txt"; 
  Scanner in = new Scanner(filename).useDelimiter("\\n");
  
  double largest;
  if (in.hasNextDouble())
      largest = in.nextDouble();
  
  while (in.hasNextDouble())
  {
      double input = in.nextDouble();
      if (input > largest)
      {
          largest = input;
      }
  }
  

Answer 2

I found solution - need to create File object and then feed it to scanner class:

String filename = "input.txt"; 
File newFile = new File(filename);
Scanner in = new Scanner(newFile);

Answer 3

Try this

import java.io.File; 
import java.io.FileNotFoundException; 
import java.util.Scanner;

public class MainClass{
public static void main(String[] args)
        throws FileNotFoundException
{
    Scanner in = new Scanner(new File("D:\\input.txt"));
    String largestNum=in.next().trim();
    double largest = Double.parseDouble(largestNum);
    while (in.hasNextDouble())
    {
        String Num=in.next().trim();
        double input = Double.parseDouble(Num);
        if (input > largest)
        {
            largest = input;
        }
    }
    in.close();
    System.out.println("Largest value: " + largest);
} }