Thread: Need help with DecimalFormat class

I need assistance with a program I wrote for class. I got it to compile and do what I want, But I was wondering how I can format my methods to to display a decimal with 1-2 decimal places. Would I create a method in my NumberAnalysis class to do it for me? Or would I declare an instance of the DecimalFormat class in my main method? I am new to programming in General and would like some feed back.

package lesson4.skowronek;
 
import java.util.Scanner;  //Needed for Scanner Class
import java.io.*;			   //Need for File and IOException
import java.text.DecimalFormat;
 
 
public class Ex8_11 {
 
 
 
 
	public static void main(String[] args) throws IOException{
 
		{
 
		DecimalFormat decformatter = new DecimalFormat("#0.00");
 
		NumberAnalysis na = new NumberAnalysis("C:\\Users\\*****\\Java Work\\Lesson 4\\src\\lesson4\\skowronek\\Numbers.txt");
		System.out.println("Lowest Number: " +  na.getLowest());
		System.out.println("Highest Number: " + na.getHighest());
		System.out.println("Total Number: " + na.getTotal());
		System.out.println("Total Average Number: " + na.getAverage());
 
		}
 
 
	}
 
 
 
}
 
 
 
 
 
 
package lesson4.skowronek;
 
import java.text.DecimalFormat;
import java.util.Scanner;
import java.io.*;
 
 
public class NumberAnalysis {
 
	double[] arrayNum;
	int cnt;
	final int ARRAY_SIZE = 12;
 
 
	NumberAnalysis(String filename) throws IOException
	{
		int cnt = 0;
		arrayNum = new double[ARRAY_SIZE];
 
 
 
 
	File numbers =  new File("C:\\Users\\******\\Java Work\\Lesson 4\\src\\lesson4\\skowronek\\Numbers.txt");
 
		Scanner inputFile = new Scanner(numbers);
		while (inputFile.hasNext() && cnt < arrayNum.length)
		{
			arrayNum[cnt] = inputFile.nextDouble();
			cnt++;
		}
	inputFile.close();
 
 
 
	}
 
	public double getLowest()
	{
	 double lowest = arrayNum[0];
	 for (int cnt = 1; cnt < arrayNum.length; cnt++)
	 {
		 if(arrayNum[cnt] < lowest)
			 lowest = arrayNum[cnt];
	 }
	 return lowest;
	}
	public double getHighest()
	{
		double highest = arrayNum[0];
		for (int cnt = 1; cnt < arrayNum.length; cnt++)
		{
			if (arrayNum[cnt] > highest)
				highest = arrayNum[cnt];
		}
		return highest;
	}
 
	public double getTotal()
	{
 
		double total = 0.0; //accumulator
 
		for (int cnt = 0; cnt < arrayNum.length; cnt++)
		{
 
		       total += arrayNum[cnt];
		}
 
		        return total;
 
	}
	public double getAverage()
	{
		double average = getTotal() / arrayNum.length;
		return average;
	}
 
}

--- Update ---

This is my output:


Lowest Number: 1.09
Highest Number: 82.76
Total Number: 367.89000000000004
Total Average Number: 30.657500000000002

--- Update ---

Think I just solved the answer to my own question, I did it by declaring double variables in my main method and called the methods and instantiated the variables into the methods... Is there a better way to do this?

package lesson4.skowronek;
 
import java.util.Scanner;  //Needed for Scanner Class
import java.io.*;			   //Need for File and IOException
import java.text.DecimalFormat;
 
 
public class Ex8_11 {
 
 
 
 
	public static void main(String[] args) throws IOException{
 
		{
			 double lowest;
			 double highest;
			 double average;
			 double total;
 
 
 
 
		NumberAnalysis na = new NumberAnalysis("C:\\Users\\*****\\Java Work\\Lesson 4\\src\\lesson4\\skowronek\\Numbers.txt");
 
		lowest = na.getLowest();
		highest = na.getHighest();
		average = na.getAverage();
		total = na.getTotal();
 
		DecimalFormat df = new DecimalFormat("#0.00");
 
		System.out.println("Lowest Number: " +  df.format(lowest));
		System.out.println("Highest Number: " + df.format(highest));
		System.out.println("Total Number: " + df.format(total));
		System.out.println("Total Average Number: " + df.format(average));
 
		}
 
 
	}
 
 
 
}

You might also look into using printf().