Grading Logic

Part of the Logic & Flow section of Coddy's C# journey — lesson 43 of 66.

Challenge

Easy

Now that we can analyze the data, let's implement a grading system to assign letter grades based on the scores. Create a class called GradingSystem with these methods:

ConvertToLetterGrade(double score): Converts a numeric score to a letter grade according to this scale:
- A: 90-100
- B: 80-89
- C: 70-79
- D: 60-69
- F: 0-59
- Invalid: Return "N/A" for any invalid score (negative or > 100)
GetStudentGrade(int[][] scoreGrid, int studentIndex): Calculates a student's average and returns their letter grade. Return "N/A" for invalid student indices.
GetClassDistribution(int[][] scoreGrid): Returns an array of integers representing the count of each letter grade in the class [A, B, C, D, F]. Base this on the average score of each student.

Try it yourself

using System; // Don't delete this line
public class GradingSystem
{
    public static string ConvertToLetterGrade(double score)
    {
        // Write your code here
        
    }
    
    public static string GetStudentGrade(int[][] scoreGrid, int studentIndex)
    {
        // Write your code here
        
    }
    
    public static int[] GetClassDistribution(int[][] scoreGrid)
    {
        // Write your code here
        
    }
}

// Required for testing - do not modify
public class DataCollector
{
    public static int[][] CreateScoreGrid(int students, int assignments)
    {
        int[][] scoreGrid = new int[students][];
        for (int i = 0; i < students; i++)
        {
            scoreGrid[i] = new int[assignments];
        }
        return scoreGrid;
    }
    
    public static bool ValidateScore(int score)
    {
        return score >= 0 && score <= 100;
    }
    
    public static int[][] PopulateWithDefaultValues(int[][] scoreGrid)
    {
        for (int i = 0; i < scoreGrid.Length; i++)
        {
            for (int j = 0; j < scoreGrid[i].Length; j++)
            {
                scoreGrid[i][j] = -1;
            }
        }
        return scoreGrid;
    }
}

public class DataEntry
{
    public static int SetStudentScore(int[][] scoreGrid, int studentIndex, int assignmentIndex, int score)
    {
        // Check for out of bounds indices
        if (studentIndex < 0 || studentIndex >= scoreGrid.Length || 
            assignmentIndex < 0 || assignmentIndex >= scoreGrid[studentIndex].Length)
        {
            return -1;
        }
        
        // Validate the score
        if (!DataCollector.ValidateScore(score))
        {
            return -2;
        }
        
        // Set the score
        scoreGrid[studentIndex][assignmentIndex] = score;
        return 0;
    }
    
    public static int UpdateAllScores(int[][] scoreGrid, int[] studentIndices, int assignmentIndex, int score)
    {
        int successCount = 0;
        
        for (int i = 0; i < studentIndices.Length; i++)
        {
            int result = SetStudentScore(scoreGrid, studentIndices[i], assignmentIndex, score);
            if (result == 0)
            {
                successCount++;
            }
        }
        
        return successCount;
    }
}

public class DataAnalyzer
{
    public static double CalculateStudentAverage(int[][] scoreGrid, int studentIndex)
    {
        // Check if student index is valid
        if (studentIndex < 0 || studentIndex >= scoreGrid.Length)
        {
            return -1;
        }
        
        int sum = 0;
        int count = 0;
        
        // Calculate sum of valid scores
        for (int j = 0; j < scoreGrid[studentIndex].Length; j++)
        {
            int score = scoreGrid[studentIndex][j];
            if (score != -1)  // Ignore ungraded assignments
            {
                sum += score;
                count++;
            }
        }
        
        // Return average or 0 if no valid scores
        return count > 0 ? (double)sum / count : 0;
    }
    
    public static double CalculateAssignmentAverage(int[][] scoreGrid, int assignmentIndex)
    {
        // Check if there are any students
        if (scoreGrid.Length == 0)
        {
            return -1;
        }
        
        // Check if assignment index is valid
        if (assignmentIndex < 0 || assignmentIndex >= scoreGrid[0].Length)
        {
            return -1;
        }
        
        int sum = 0;
        int count = 0;
        
        // Calculate sum of valid scores for the assignment
        for (int i = 0; i < scoreGrid.Length; i++)
        {
            if (assignmentIndex < scoreGrid[i].Length)
            {
                int score = scoreGrid[i][assignmentIndex];
                if (score != -1)  // Ignore ungraded assignments
                {
                    sum += score;
                    count++;
                }
            }
        }
        
        // Return average or 0 if no valid scores
        return count > 0 ? (double)sum / count : 0;
    }
    
    public static int[] FindHighestScore(int[][] scoreGrid)
    {
        int highestStudentIndex = 0;
        int highestAssignmentIndex = 0;
        int highestScore = -1;
        
        // Search for the highest score
        for (int i = 0; i < scoreGrid.Length; i++)
        {
            for (int j = 0; j < scoreGrid[i].Length; j++)
            {
                int currentScore = scoreGrid[i][j];
                if (currentScore > highestScore)
                {
                    highestScore = currentScore;
                    highestStudentIndex = i;
                    highestAssignmentIndex = j;
                }
            }
        }
        
        return new int[] { highestStudentIndex, highestAssignmentIndex, highestScore };
    }
}