How can I solve these problems using my program? (Many problems are explained internally)

Question

This question is not for the faint of heart and will take a lot of time.

I am learning Java, and I was wondering if anyone could go through my program to tell me what I did wrong and how I can fix it so that I can learn.

My whole program (if necessary): http://pastie.org/private/xpbgpypetvfmivcs88gbcq

Appointment:

You cannot use global variables! You were asked to write a program to evaluate the results of a true false quiz and display the results in a tabular form. The test consists of 10 questions. The data file for this problem consists of 1 set of correct answers (answer) in line 1 and subsequent lines containing the four-digit student identification number and then this student has 10 answers. (The number of students taking the quiz is currently unknown.)

The data file is in the form:

TFFTFTTFTT

0461 TTFTTFTFTT

3218 TFFTTTTTFT

.....................

....................

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: A (10), B (9), C (8-7), D (6-5), F (4-0).

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• A, B, C, D F .

EDIT:

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int[] numericGrade = computeNumericGrade(answerKey, studentAnswers);
      int[] letterGrade = computeLetterGrade(numericGrade);
      double average = average(numericGrade);
      int gradeTally = gradeTally(letterGrade);
      int studentCount = studentCount(numericGrade);

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public static int[] computeNumericGrade(int[] answerKey, int[] studentAnswers) {
      int[] numericGrade = new int[50];
      int total = 0;
      for(int i = 0; i < 50;i++) {
        for(int a = 0;a == 10;a++) {
          total = studentAnswers[i].charAt(a);
          if(total == answerKey[i]) numericGrade[i]++;
        }
      }
    return numericGrade;
    }

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public static int gradeTally(String[] letterGrade) {
      int a, b, c, d, f = 0;
      for(int i = 0;i < letterGrade.length;i++) {
        if(letterGrade[i] == 'A') a++;
        else if (letterGrade[i] == 'B') b++;
        else if (letterGrade[i] == 'C') c++;
        else if (letterGrade[i] == 'D') d++;
        else if (letterGrade[i] == 'F') f++;
      }
      return a + b + c + d + f;
    }

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public static String[] getData() throws IOException {
      int[] studentID = new int[50];
      String[] studentAnswers = new String[50];
      int total = 0;

      String line = reader.readLine();
      strTkn = new StringTokenizer(line);
      String answerKey = strTkn.nextToken();

      while(line != null) {
        studentID[total] = Integer.parseInt(strTkn.nextToken());
        studentAnswers[total] = strTkn.nextToken();
        total++;
      }
    return studentAnswers;
    }

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Answer 1

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Answer 2

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someField cannot be resolved

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public static String[] getData() throws IOException {
  // other code

  String[] studentAnswers = new String[50];

  // other code 

  String answerKey = strTkn.nextToken();

  // other code
}

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 // this is a new class, and will have to be saved in a file called Student.java
public class Student {

    // these are field declarations
    private int id;
    private String answers;

    // this is the constructor, it creates a new instance of Student
    public Student(int newStudentsId, String newStudentsAnswers) {
        // these lines take the parameters (in brackets on the line above)
        // and assign them to the fields of this instance
        this.id = newStudentsId;
        this.answers = newStudentsAnswers;
    }

    // after this you could have getters for the fields,
    // these are often referred to as "accessors" in introductory texts
    // this is all I'll give you of this example, to get you started

} // End of class Student.java

---

, , :

Incompatible operand types String and char

:

public static int gradeTally(String[] letterGrade) {
  // other code
    if(letterGrade[i] == 'A') a++;  // error on this line

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• letterGrade char[] letterGrade, ( ).

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Cannot invoke charAt(int) on the primitive type int

:

total = studentAnswers[i].charAt(a);

charAt - String, studentAnswers[i] String. int[] studentAnswers, " ".

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Answer 3

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Answer 4

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