Writing to a text file

[Alex Breault]

How would i complete the fileCreate method to write to a text file called "Results.txt" with this output?
819283761,15,100.0,30,A
834987341,9,60.0,18,D
899991828,13,86.66666666666667,26,B
888181818,9,60.0,18,D
892823736,6,40.0,12,F

/*
* Proj5
* Alex Breault / Friday 7:30 Varshney
*
* Scantron grader from text file
*/




import java.util.*;
import java.text.*;
import java.io.*;


public class Proj5 {
	
	/* method main
	method to call other methods
	 */
	
	public static void main (String[] args) {
		String file = inFile();
		
		Scanner s = new Scanner(System.in);
		System.out.print("Please enter the number of questions on the exam: ");
		int questions = s.nextInt();
		System.out.print("Please enter the number of points per questions: ");
		int points = s.nextInt();
		
		double[] scoreInfo = new double [2];
		
		char[] key = createKey(questions);
		
		String [][] sArray = readFile(file);
		int i = 0;
		
		
		System.out.println("Student ID	#Correct	%Correct	Score	Grade");
		
		while (sArray [1][i] != null) {
			int numberCorrect = gradeQuiz(key, sArray [1][i]);
			
			scoreInfo = calcAverage(numberCorrect, questions, points, key, scoreInfo[1]);
			i++;
			
			
			displayScores(numberCorrect, scoreInfo[0], sArray[0][i-1], points);
			
			fileCreate(numberCorrect, scoreInfo[0], sArray[0][i-1], points);
		}
		
		
		
	}
	
	/* method inFile
	method to read in file
	no parameters
	returns file  */
	
	public static String inFile() {
		/* method to read in file
		*/
		Scanner s = new Scanner(System.in);
		String line = null;
		
		System.out.println("Enter name of quiz file (i.e. quizscores.txt): ");
		String file = s.nextLine();
		
		try{
             FileReader fileReader = new FileReader(file); //Creates a file reader object called "fileReader"
			 BufferedReader bufferedReader = new BufferedReader(fileReader); //wraps "fileReader" it in a Buffered reader called "bufferedReader"
			
        } 
		catch (FileNotFoundException ex) {
			System.out.println("Error! File does not exist");
		}
	
		return file;
	}
	
	
	
	/* method readFile
	method to read file contents
	@param wid, wildcat ID array
	@param answers, array full of key answers
	@param file, text file with student answers
	
	@returns students test answers   */
	
	
	
	public static String [][] readFile (String file) {
		String [][] sArray = new String [2][50];
		int lineNumber = 1;
		String line = null;
		try {
			
			FileReader fileReader = new FileReader(file);
			BufferedReader bufferedReader =  new BufferedReader(fileReader);
			
			while ((line = bufferedReader.readLine()) != null) {
				String [] temp = line.split(",");
				
				for (int i = (lineNumber); (i - lineNumber) < temp.length; i++) {
					
					if ((i - lineNumber)  == 0) {
						
						sArray [0][lineNumber-1] = temp [i - lineNumber]; // wildcat id
					}
					else{
						
						sArray [1][lineNumber-1] = temp [i - lineNumber]; //answers
					}
					
					
				}
				lineNumber++;
			}
			
		bufferedReader.close();
		}
		catch (IOException ex) {
			System.out.println("There was a problem reading " + ex);
		}
		
	
		return sArray;
	}
	
	/* method createKey
	method to read in answer key from user
	@param questions, number of questions on test
	@return ??? */
	
	
	public static char [] createKey (int questions) {
		Scanner s = new Scanner(System.in);
		char [] key = new char[questions];
		
		System.out.println("Please enter the answers for the following questions");
		System.out.println("where 'T' = true, 'F' = false, or A, B, C, D, E for multiple choice");
        for (int i=0; i<key.length; i++)
	    {
			System.out.print((i+1) + ") ");
			char userInput = s.nextLine().toUpperCase().charAt(0);
			
			switch (userInput) {
				
				case 'T': 
					key[i] = '1';
				break;
				
				case 'F':
					key[i] = '2';
				break;
				
				case 'A':
					key[i] = '1';
				break;
				
				case 'B':
					key[i] = '2';
				break;
				
				case 'C':
					key[i] = '3';
				break;
				
				case 'D':
					key[i] = '4';
				break;
				
				case 'E':
					key[i] = '5';
				break;
				
				default:
					System.out.println("Incorrect answer");
					i--;
				break;
			}
			
	    }
		
		
		
		return key;
	} 
	
	/* method gradeQuiz
	method to compare answer key to student answers
	@param answers array, array containing students answers
	@param key array, array containing answer key
	@param questions, number of questions
	@return numberCorrect, number of questions correct */
	
	
	public static int gradeQuiz (char [] key, String studentAnswers) {
		
		char [] studentAnswersArray = studentAnswers.toCharArray();
		int numberCorrect = 0;
		
		for (int t = 0; t < key.length; t++) {
			if (key [t] == studentAnswersArray [t]) {
				numberCorrect++;
			}
		}
		
		
		return numberCorrect;
	}
	
	/* method letterGrade
	method that calculates the letter grade on test
	@param percentCorrect, calculates letter grade based on percentCorrect
	@return letterGrade of test */
	
	
	public static char getLetterGrade (double percentCorrect) {
		
		
		char letterGrade = 'A';
		
		if (percentCorrect <= 100 && percentCorrect >= 90) {
			
			letterGrade = 'A';
        } 
        else if (percentCorrect <= 89.9 && percentCorrect >= 80) {
			
			letterGrade = 'B';
        }
        else if (percentCorrect <= 79.9 && percentCorrect >= 70) {
           
			letterGrade = 'C';
        }
        else if (percentCorrect <= 69.9 && percentCorrect >= 60) {
            
			letterGrade = 'D';
        }
        else {
            
			letterGrade = 'F';
        }
		return letterGrade;
	}
	
	/* method calcAverage
	method to calculate average on test
	@param numberCorrect, number of questions correct
	@param numberStudents, number of students that took the test
	@return average, average score on test */
	
	
	public static double [] calcAverage (int numberCorrect, int questions, int points, char [] key, double averageScore) {
		
		
		questions = key.length;
		double percentCorrect;
		
		percentCorrect = (((double)numberCorrect/ (double)questions) * 100);
		
		
		averageScore += percentCorrect;
		
		
		
		double[] scoreInfo = {percentCorrect, averageScore};
		
		return scoreInfo;
	}
	
	/* method displayScores
	method to display the scores at the end of the program
	@param average, average score on test
	@param highScore, high score on test
	@param lowScore, low score on test
	@return no return */
	
	
	public static void displayScores (int numberCorrect, double percentCorrect, String wid, int points) {
		DecimalFormat df = new DecimalFormat ("###.#%");
		
		int totalScore = (numberCorrect * points);
		
		
		
		System.out.println(wid + "	" + numberCorrect + "	" + df.format(percentCorrect/100) + "	" + totalScore + "	" + getLetterGrade(percentCorrect));
		
		
		
		
	}
	
	/* method fileCreate
	method to create a file with the results */
	
	
	

	public static void fileCreate () {
		try {
           
		   
		   
        }
        catch(IOException ex) {
            System.out.println(
                "Error writing to file '" + file + "'");
            
        }
		
		System.out.println("Results.txt file created");
		
	}
	
	
	
}

[Carey Brown]

Alex Breault wrote:How would i complete the fileCreate method to write to a text file called "Results.txt" with this output?
819283761,15,100.0,30,A
834987341,9,60.0,18,D

I suggest looking in the Javadoc in the java.io package for appropriate classes to use. Specifically, character oriented classes and not byte oriented classes. And, of course, you should be looking for a class that supports output and not input. You may also want to keep an eye out for classes that buffer their data, not absolutely necessary, but more efficient.

There's also a lot of I/O tutorials available online.

Show us what you've come up with and let us know about any specific issues you're having.

[Alex Breault]

	public static void fileCreate (int numberCorrect, double percentCorrect, String wid, int points) {
		try {
           
		// Creates a textfile of entered input
			int totalScore = (numberCorrect * points);
			Scanner s = new Scanner(System.in);
			PrintWriter pw = new PrintWriter(new FileWriter("Results.txt"));
			DecimalFormat df = new DecimalFormat ("###.#%");

			
			pw.println(wid + "," + numberCorrect + "," + df.format(percentCorrect/100) + "," + totalScore + "," + getLetterGrade(percentCorrect));

			pw.close();

		   
		   
        }
        catch(IOException ex) {
            System.out.println(
                "Error writing to file");
            
        }
		
		
		
	}

This is the method now but it does not save all info into the text file, just the last students

[Ahmed Bin S]

Because each time you call fileCreate(), you are creating a new file, so anything you wrote to the file the previous time you called fileCreate(), gets overwritten.

BTW, you might also want to check getLetterGrade(), some of your students might be very angry, after all, if they scored 89.91%, they would rightly expect to be awarded a B grade, and not a F grade.

[Carey Brown]

I would modify your fileCreate() to take a PrintWriter object. Actually, a better name for the method would be something like "fileWrite()". Then outside of your main loop, open up the PrintWriter, and inside your loop call fileWrite(). And don't forget to call close() when your loop completes.

[Campbell Ritchie]

For a simple text file I would use a Formatter. Get rid of things like DecimalFormat; look on that as legacy code.