# Exercise Solutions: Classes and Objects, Part 2¶

## The `getGradeLevel` Method¶

This method returns the student’s level based on the number of credits they have earned: Freshman (0-29 credits), Sophomore (30-59 credits), Junior (60-89 credits), or Senior (90+ credits).

 ``` 1 2 3 4 5 6 7 8 9 10 11``` ```public static String getGradeLevel(int credits) { if (credits <= 29){ return "freshman"; } else if (credits <= 59){ return "sophomore"; } else if (credits <= 89) { return "junior"; } else { return "senior"; } } ```

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## The `addGrade` Method¶

This method accepts two parameters—a number of course credits and a numerical grade (0.0-4.0). With this data, you need to update the student’s GPA.

### GPA Information¶

GPA is computed via the formula:

gpa = (total quality score) / (total number of credits)

1. The quality score for a class is found by multiplying the letter grade score (0.0-4.0) by the number of credits.

2. The total quality score is the sum of the quality scores for all classes.

For example, if a student received an “A” (worth 4 points) in a 3-credit course and a “B” (worth 3 points) in a 4-credit course, their total quality score would be: 4.0 * 3 + 3.0 * 4 = 24. Their GPA would then be 24 / 7 = 3.43.

### Determine the New GPA¶

To update the student’s GPA:

1. Calculate their current total quality score by using the formula `gpa * numberOfCredits`.

2. Use the new course grade and course credits to update their total quality score.

3. Update the student’s total `numberOfCredits`.

4. Compute their new GPA.

 ```1 2 3 4 5 6``` ```public void addGrade(int courseCredits, double grade) { double totalQualityScore = this.gpa * this.numberOfCredits; totalQualityScore += courseCredits * grade; this.numberOfCredits += courseCredits; this.gpa = totalQualityScore/this.numberOfCredits; } ```

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## `toString` and `equals`¶

1. Add custom `equals()` and `toString()` methods to the `Student` class.

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21``` ```public String toString() { String studentReport = String.format("%s is a %s with %d credits and a GPA of %.2f", this.name, this.getGradeLevel(this.numberOfCredits), this.getNumberOfCredits(), this.getGpa()); return studentReport; } public boolean equals(Object toBeCompared) { if (toBeCompared == this) { return true; } if (toBeCompared == null) { return false; } if (toBeCompared.getClass() != getClass()) { return false; } Student theStudent = (Student) toBeCompared; return theStudent.getStudentId() == getStudentId(); } ```

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