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Thread: File Reading code doesn't work

  1. #1
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    Default File Reading code doesn't work

    My code needs to print certain results to a file if the user types something, and if they type nothing just print it to the screen. I wrote the code, and am including it below, but once my program prompts the user it doesn't do anything and I don't understand why. I know the code is long, but is fairly logically laid out. If anyone knows why please give me some insights, Thank You.
    import java.util.*;
    import java.io.*;
     
    public class Project4{
    	public static void main(String[] args)
    		throws FileNotFoundException {
    		Scanner input = new Scanner(System.in);
    		System.out.print("File Name:");
    		String fileName = input.nextLine();
    		Scanner console = new Scanner(new File(fileName));
    		int totalNumbers = console.nextInt();
    		double[] filearray;
    		filearray = new double[totalNumbers];
    		for (int i = 0; i < totalNumbers; i++)
    			filearray[i] = console.nextDouble();
    		System.out.print("Output [type a file name, or push return");
    		System.out.print(" to output to screen]: ");
    		String s = input.next();
    		System.out.print("There are " + totalNumbers);
    		System.out.println(" numbers in your input file");
    		if (s.length() == 0){
    			printResults(filearray);
    		} else {
    			writeResultsToFile(filearray);
    		}
    		Arrays.sort(filearray);
    		}
     
     
    	public static double calculateMax(double[] filearray){
    		double maximum = filearray[0];
    		for (int i = 1; i < filearray.length; i++){
    			if (filearray[i] > maximum){
    				maximum = filearray[i];
    				}
    			}
    			return maximum;
    			}
     
    	public static double calculateMin(double[] filearray){
    		double minimum = filearray[0];
    			for (int i = 1; i < filearray.length; i++){
    				if (filearray[i] < minimum){
    					minimum = filearray[i];
    					}
    				}
    				return minimum;
    				}		
     
     
    	public static double calculateMean(double[] filearray){
    		double sum = 0;
    			//calculates sum
    		for (int i = 0; i < filearray.length; i++){
    			sum = sum + filearray[i];
    			}
    			//calculates average
    			double mean = (sum / filearray.length);
    			return mean;
    	}
     
    	public static double calculateMedian(double[] filearray){
    		  int middle = (filearray.length+1)/2;
        if (filearray.length%2 == 1) {
            // Odd number of numbers -- return the middle one.
            return filearray[middle];
        } else {
           // Even number -- return average of middle two
           // Must cast to double before division.
           return (filearray[middle-1] + filearray[middle]) / 2.0;
        }
    }
     
    	public static double calculateMode(double[] filearray){
    		double maxValue = -1;
    		int maxCount = 0;
    		for (int i = 0; i < filearray.length; i++){
    			//counts number of times number is in array
    			int count = 0;
    			for(int j = 0; j < filearray.length; j++){
    				if(filearray[j] == filearray[i]){
    					count++;
    					}
    				}
    			//remember which was max
    			if (count > maxCount){
    				maxValue = filearray[i];
    				maxCount = count;
    			}
    		}
    	return maxValue;
    	}
     
    static double calculateStandardDeviation(double[] filearray, double meanOfArray){
            double squareOfDeviations = 0;
    		  for(int i = 0; i < filearray.length; i++){        
               double diff = filearray[i] - meanOfArray;
               squareOfDeviations = squareOfDeviations + (diff * diff);
     
            }
            double deviance = (squareOfDeviations/filearray.length); 
    		  return deviance;
     
            } 
    	public static void printResults(double[] filearray){
    		double maximumOfArray = calculateMax(filearray);
    		double minimumOfArray = calculateMin(filearray);
    		double modeOfArray = calculateMode(filearray);
    		double meanOfArray = calculateMean(filearray);
    		double medianOfArray = calculateMedian(filearray);
    		double standardDeviationOfArray = 
    			calculateStandardDeviation(filearray, meanOfArray);
    		System.out.println("Max: " + maximumOfArray);
    		System.out.println("Min: " + minimumOfArray);
    		System.out.println("Mode: " + modeOfArray);
    		System.out.println("Mean: " + meanOfArray);
    		System.out.println("Median " + medianOfArray);
    		System.out.println("Standard Deviation: " + standardDeviationOfArray);
    	}
     
    	public static void writeResultsToFile(double[] filearray)
    		throws FileNotFoundException{
    		PrintStream output = 
    		new PrintStream(new File("results.txt"));
    		double maximumOfArray = calculateMax(filearray);
    		double minimumOfArray = calculateMin(filearray);
    		double modeOfArray = calculateMode(filearray);
    		double meanOfArray = calculateMean(filearray);
    		double medianOfArray = calculateMedian(filearray);
    		double standardDeviationOfArray = 
    			calculateStandardDeviation(filearray, meanOfArray);
    		output.println("Max: " + maximumOfArray);
    		output.println("Min: " + minimumOfArray);
    		output.println("Mode: " + modeOfArray);
    		output.println("Mean: " + meanOfArray);
    		output.println("Median " + medianOfArray);
    		output.println("Standard Deviation: " + standardDeviationOfArray);
    	}
     
    }
    Last edited by copeg; April 25th, 2011 at 08:37 AM.


  2. #2
    Super Moderator copeg's Avatar
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    Default Re: File Reading code doesn't work

    I suggest boiling the code down to an SSCCE to narrow the problem down to the minimal amount of code. There is a lot of code to wade through (and please use the code tags).

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