CODEWITHSUNDEEP
javamethods
KrissyMichaelsson
KrissyMichaelsson

Reputation: 89

What is wrong with my letter to number grade calculator?

I'm trying to make a method with takes a letter grade and returns a numeric grade. It only works tho for letters without pluses or minuses. Here's what I have:

public class Grade{
  private String letterGrade;
  private double numericGrade;

  public Grade(String letterGrade)
  {
    this.letterGrade = letterGrade;
    this.numericGrade = numericGrade;
  }

  public void getNumericGrade()
  {
    if (letterGrade.equals("A"))
    {
      numericGrade = 4.0;
    }
    else if (letterGrade.equals("B"))
    {
      numericGrade = 3.0;
    }
    else if (letterGrade.equals("C"))
    {
      numericGrade = 2.0;
    }
    else if (letterGrade.equals("D"))
    {
      numericGrade = 1.0;
    }
    else if (letterGrade.equals("F"))
    {
      numericGrade = 0.0;
    }

    if (letterGrade.substring(1).equals("+"))
    {
      numericGrade += .3;
    }
    else if (letterGrade.substring(1).equals("-"))
    {
      numericGrade -= .3;
    }

    System.out.println(numericGrade);

  }

It gives 4.0 for "A", but it gives -0.3 for A-. Whats going on here?

Upvotes: 2

Views: 63

Answers (2)

Richard Campbell
Richard Campbell

Reputation: 3621

Well, walk through it. If you pass "A-", then "A-" is not equal to "A", so you don't get the 4.0 (or the other letter grades). But you do then get the -0.3 for the minus...

Upvotes: 1

Elliott Frisch
Elliott Frisch

Reputation: 201477

Change your equals to startsWith calls (because "A+" is not equal to "A"), and do the initialization in your constructor (and initializing numericGrade to itself should be giving you a warning). A getter should return the value (not set it). Something like,

private String letterGrade;
private double numericGrade;

public Grade(String letterGrade) {
    this.letterGrade = letterGrade;
    if (letterGrade.startsWith("A")) {
        numericGrade = 4.0;
    } else if (letterGrade.startsWith("B")) {
        numericGrade = 3.0;
    } else if (letterGrade.startsWith("C")) {
        numericGrade = 2.0;
    } else if (letterGrade.startsWith("D")) {
        numericGrade = 1.0;
    } else if (letterGrade.startsWith("F")) {
        numericGrade = 0.0;
    }

    if (letterGrade.substring(1).equals("+")) {
        numericGrade += .3;
    } else if (letterGrade.substring(1).equals("-")) {
        if (numericGrade > 0) {
            numericGrade -= .3; // <-- or an F- is -0.3
        }
    }
}

public double getNumericGrade() {
    // System.out.println(numericGrade);
    return numericGrade;
}

Upvotes: 2

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