Thread: help with codoe

The purpose of the code is to write a name and test score into a new file. The main problem i get is that it doesn't write the name in the file but it is able to write the test scores. Also I have a section where i check for the largest and smallest test score and that seems to not work either.
The error occurs as soon as I enter a name when promted.

 
import java.io.*;
import java.text.NumberFormat;
import java.util.Scanner;
public class statsP2 {
 
 
	public static void main(String[] args) {
 
 
 
		Scanner input = new Scanner(System.in);
		FileReader in;
		FileWriter out;
		BufferedReader readFile;
		BufferedWriter writeFile;
		String name;
		Double score;
		String score1;
		String fileName;
		int numScores;
		double totalScores = 0;
		double avgScore;
		double smallest;
		double largest;
		NumberFormat percent = NumberFormat.getPercentInstance();
		/* prompt user for file name 
		System.out.print("Enter the name of the application file: ");
		fileName = input.nextLine();
		*/
		File dataFile = new File("testName2.txt");
 
 
 
 
 
try {
			out = new FileWriter(dataFile);
			writeFile = new BufferedWriter(out);
			// writes name to file
			System.out.println("Enter your name: ");
				name=input.next();
				writeFile.write(name);
				writeFile.newLine();
 
				System.out.println("How many scores would you like to enter? : ");
			 numScores = input.nextInt();
			 double[] myNum = new double[numScores];
				System.out.println("Enter " + numScores + " class score: ");
				for( int i =0; i<numScores; i++) {
					 score=input.nextDouble();
					  totalScores += score;
				writeFile.write(String.valueOf(score));
				writeFile.newLine();
				}
 
				avgScore = totalScores/numScores;
				in = new FileReader(dataFile);
				readFile = new BufferedReader(in);
				name=readFile.readLine();
				System.out.println(name);
	    		while ((score1 = readFile.readLine()) != null) {
	    			for( int i =0; i<=numScores; i++) {
						 myNum[i] = Double.parseDouble(score1);
 
					}
 
				}
	    		largest =myNum[0];
   			 smallest=myNum[0] ;
   			for (int i = 1; i < myNum.length; i++) {
   				   if (myNum[i] > largest)
   				    largest = myNum[i];
   				   else if (myNum[i] < smallest)
   				    smallest = myNum[i];
   				  }
	    		System.out.print("\n" + name + " Average = " + percent.format(avgScore/100)
	    		+ "\n" + "Lowest Score :" + smallest + "\n" + "Highest Score: " + largest);
 
		writeFile.close();
		out.close();
 
		readFile.close();
    		in.close();
    	} catch (FileNotFoundException e) {
			System.out.println("File does not exist or could not be found.");
			System.err.println("FileNotFoundException: " + e.getMessage());
		} catch (IOException e) {
			System.out.println("Problem reading file.");
    		System.err.println("IOException: " + e.getMessage());
    	}
	}
 
}

I am trying to build a max heap java class for item objects, so I can solve the knapsack problem and implement greedy algorithms to do so. Item class includes weight, value, Id(to distinguish items), and most importantly a priority factor:

public class Items {
double weight;
double value;
double priorityFactor;
int ID;

//constructor for items class
public Items(int weight, int value, int id, int priorityFactor)
{
this.weight=weight;
this.value=value;
this.ID=id;
this.priorityFactor = priorityFactor;
} //end constructor



Now the issue that I'm facing is in the max heap class, which is supposed to build me a max heap tree based on the priority factor. Meaning that I should have an array of item objects: private Items[] array

What I'm finding it difficult to implement is how cam I insert those items in the array based on the priority factor. If I do this, I think I will be able to implement the greedy algorithms. How to handle this?

        try {
            /*--------------------------------------------------------------*/
            Scanner input = new Scanner(System.in);
            Scanner reader = new Scanner(new File("path"));
            BufferedWriter writer = new BufferedWriter(new FileWriter(new File("path")));
            double totalScore = 0, max = Integer.MIN_VALUE, min = Integer.MAX_VALUE;
            /*--------------------------------------------------------------*/
 
            System.out.print("Enter your name: ");
            String name = input.next();
            writer.write(name+"\n");
            System.out.print("How many scores would you like to enter: ");
            int numScores = input.nextInt();
            System.out.println("Enter " + numScores + " class score: ");
            for(int i = 0; i < numScores; i++) {
                double score = input.nextDouble();
		totalScore += score;
		writer.write(score+"\n");
            }
            writer.close();
            double average = totalScore/numScores;
            name=reader.nextLine();
            System.out.println(name);
            for(int i = 0; i < numScores; i++) {
                double num = Double.parseDouble(reader.next());
                max = max < num ? num : max;
                min = min > num ? num : min;
            }
            System.out.println("\n" + name + " Average = " + average + "\n" + "Lowest Score :" + min + "\n" + "Highest Score: " + max);
    	} catch (FileNotFoundException e) {
            System.out.println("File does not exist or could not be found.");
            System.err.println("FileNotFoundException: " + e.getMessage());
        } catch (IOException e) {
            System.out.println("Problem reading file.");
            System.err.println("IOException: " + e.getMessage());
    	}

--- Update ---

what is the priority factor?