Question

I am having trouble reading from a simple text file and cannot seem to figure out why. I have done this before, and I am unsure as to what the issue is. Any help would be appreciated!

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

public class CS2110TokenReader {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

        File theFile = new File("data1.txt");
        Scanner scnFile = new Scanner(theFile);

        try {
            scnFile = new Scanner(theFile);
        } catch (Exception e) {
            System.exit(1);
        }
        while (theFile.hasNext()) {
            String s1 = theFile.next();
            Double d1 = theFile.nextDouble();

            System.out.println(s1 + "   " + d1);
        }

    }

}

---

Exception in thread "main" java.lang.Error: Unresolved compilation problems: 
    The method hasNext() is undefined for the type File
    The method next() is undefined for the type File
    The method nextDouble() is undefined for the type File

    at CS2110TokenReader.main(CS2110TokenReader.java:20)

---

It will not even scan for the next line. That is my objective. To scan and read.

Answer 1

while (theFile.hasNext()) {  // change to `scnFile.hasNext()`
    String s1 = theFile.next();  // change to `scnFile.next()`
    Double d1 = theFile.nextDouble();  // change to `scnFile.nextDouble()`

    System.out.println(s1 + "   " + d1);
}

You are invoking the method of Scanner class on File reference. Replace theFile with scnFile in all the invocation.

Secondly, you are invoking next() and nextDouble(), but are only checking for hasNext() once. That may throw you NoSuchElementException at some point of time. Make sure that, you have an input to read, before you actually read it.