Somebody please take a look at this

[David Barry]

Hi everybody. I have taken a different approach to the writing of this code. However, when I try to run it, it says possible loss of precision and highlights this line: " theTemps[index] = inFile.next();". I am wondering why it says possible loss of precision. Thanks

   
/**
 * This program calculates the monthly Heat Index for a specific city. 
 * 
 * @author John D. Barry 
 * @date  January 30, 2009
 */
import java.util.Scanner;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.File;
class HeatIndex

{
       public static void main (String [ ] args) throws IOException
       {
           

           double index = 0.0;
           double [] theTemps = new double[14];
           File temps = new File("KeyWestTemp.txt");
           Scanner inFile = new Scanner(temps);
           
           while (inFile.hasNext())
           {
            
                theTemps[index] = inFile.next();

           }

           inFile.close();

           


            

            

            
            

            


            
            

       

    }
}

 

[Mike Curwen]

that's an interesting error message alright.

well think of this: what is an array index only allowed to be? (hint: it's not a double).

once you fix that, you'll have your next problem (incompatible types)... but fix the index problem first.

(and once you fix that, you'll have your third problem, but at least it will compile).

[David Barry]

ok. and what is the purpose of the array index again? I forget.

[fred rosenberger]

David Barry wrote:ok. and what is the purpose of the array index again? I forget.

think of an array as an egg carton - it simply holds things. The index is used to identify the SPECIFIC egg in the carton. So, would you say "Take egg #3.2 out of the egg carton"?

probably not. you'd probably only use whole numbers - i.e. numbers without a decimal part.

[David Barry]

What do you think my third problem is? I now have this code that compiles, but does not print out my doubles from the text file.

 
/**
 * This program calculates the monthly Heat Index for a specific city. 
 * 
 * @author John D. Barry 
 * @date  January 30, 2009
 */
import java.util.Scanner;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.File;
class HeatIndex

{
       public static void main (String [ ] args) throws IOException
       {
           

           int index = 0;
           double [] theTemps = new double[14];
           File temps = new File("KeyWestTemp.txt");
           Scanner inFile = new Scanner(temps);
           
           while (inFile.hasNextDouble())
           {
            
                theTemps[index] = inFile.nextDouble();
                

           }
           System.out.println(theTemps);

           inFile.close();
    }
}

   

[Ernest Friedman-Hill]

You can't display the contents of an array this way:

System.out.println(theTemps);

You have to use a loop and print each element. There are a million ways to do this, but here's one:

 for (double d: theTemps) 
    System.out.printf("%.2f ", d);
System.out.println();

[Mike Curwen]

David Barry wrote:What do you think my third problem is? I now have this code that compiles, but does not print out my doubles from the text file.

 

           int index = 0;
           double [] theTemps = new double[14];
           File temps = new File("KeyWestTemp.txt");
           Scanner inFile = new Scanner(temps);
           
           while (inFile.hasNextDouble())
           {
            
                theTemps[index] = inFile.nextDouble();
                

           }

   

Your 3rd problem is that your index is not moving. To take someone else's example, you are smashing each new egg you pick up from inFile, into the same spot, every time through the loop. What happens to the metaphorical eggs, is what happens to your previous numbers.

you need to be incrementing the value of index, each time through the loop.

Finally, you might encounter a fourth problem (ponder what happens when there are more than 14 values in the file you are reading)

[Campbell Ritchie]

You would have done better to post this as a continuation of your earlier thread. And I have already told you "Somebody please take a look at this" is not a suitable thread title.

I am not getting at you. We want to help, but it is more difficult if you don't keep threads together, or use such vague titles.