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Thread: Need help with DecimalFormat class

  1. #1
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    Default 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));
     
    		}
     
     
    	}
     
     
     
    }


  2. #2
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    Default Re: Need help with DecimalFormat class

    You might also look into using printf().

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