Module: CgpaCalculator

Defined in:
lib/cgpa_calculator.rb

Overview

CGPA Calculator - A lightweight Ruby library for calculating GPA, CGPA, and SGPA. Supports 4.0 and 5.0 grading scales.

Homepage: https://gpacalc.app

Constant Summary collapse

VERSION = 
"1.0.1"
GRADE_POINTS_4 = 
{
  "A+" => 4.0, "A" => 4.0, "A-" => 3.7,
  "B+" => 3.3, "B" => 3.0, "B-" => 2.7,
  "C+" => 2.3, "C" => 2.0, "C-" => 1.7,
  "D+" => 1.3, "D" => 1.0, "D-" => 0.7,
  "F" => 0.0
}.freeze
GRADE_POINTS_5 = 
{
  "A" => 5.0, "B" => 4.0, "C" => 3.0,
  "D" => 2.0, "E" => 1.0, "F" => 0.0
}.freeze

Class Method Summary collapse

Class Method Details

.calculate_cgpa(semesters) ⇒ Float

Calculate cumulative GPA across multiple semesters

Parameters:

  • semesters (Array<Hash>) —

    each with :gpa (Float) and :credits (Numeric)

Returns:

  • (Float) —

    the cumulative GPA

Raises:

  • (ArgumentError) 


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# File 'lib/cgpa_calculator.rb', line 51

def calculate_cgpa(semesters)
  raise ArgumentError, "semesters must be a non-empty array" if semesters.nil? || semesters.empty?

  total_points = 0.0
  total_credits = 0.0

  semesters.each do |sem|
    gpa = sem[:gpa].to_f
    credits = sem[:credits].to_f
    total_points += gpa * credits
    total_credits += credits
  end

  (total_points / total_credits).round(2)
end

.calculate_gpa(courses, scale: 4.0) ⇒ Float

Calculate GPA for a list of courses

Parameters:

  • courses (Array<Hash>) —

    each with :grade (String) and :credits (Numeric)

  • scale (Float) (defaults to: 4.0) —

    4.0 or 5.0 (default: 4.0)

Returns:

  • (Float) —

    the calculated GPA

Raises:

  • (ArgumentError) 


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# File 'lib/cgpa_calculator.rb', line 28

def calculate_gpa(courses, scale: 4.0)
  raise ArgumentError, "courses must be a non-empty array" if courses.nil? || courses.empty?

  grade_map = scale == 5.0 ? GRADE_POINTS_5 : GRADE_POINTS_4
  total_points = 0.0
  total_credits = 0.0

  courses.each do |course|
    grade = course[:grade].to_s.upcase.strip
    credits = course[:credits].to_f
    raise ArgumentError, "Unknown grade: #{grade}" unless grade_map.key?(grade)
    raise ArgumentError, "Credits must be positive" unless credits > 0

    total_points += grade_map[grade] * credits
    total_credits += credits
  end

  (total_points / total_credits).round(2)
end

.gpa_to_letter(gpa) ⇒ String

Convert a GPA to a letter grade

Parameters:

  • gpa (Float) —

    the GPA value

Returns:

  • (String) —

    the letter grade



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# File 'lib/cgpa_calculator.rb', line 92

def gpa_to_letter(gpa)
  case gpa
  when 3.85..4.0 then "A"
  when 3.5...3.85 then "A-"
  when 3.15...3.5 then "B+"
  when 2.85...3.15 then "B"
  when 2.5...2.85 then "B-"
  when 2.15...2.5 then "C+"
  when 1.85...2.15 then "C"
  when 1.5...1.85 then "C-"
  when 1.15...1.5 then "D+"
  when 0.85...1.15 then "D"
  when 0.5...0.85 then "D-"
  else "F"
  end
end

.percentage_to_gpa(percentage) ⇒ Float

Convert a percentage score to GPA on a 4.0 scale

Parameters:

  • percentage (Numeric) —

    the percentage score (0-100)

Returns:

  • (Float) —

    the equivalent GPA

Raises:

  • (ArgumentError) 


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# File 'lib/cgpa_calculator.rb', line 70

def percentage_to_gpa(percentage)
  raise ArgumentError, "Percentage must be between 0 and 100" unless percentage.between?(0, 100)

  case percentage
  when 93..100 then 4.0
  when 90..92 then 3.7
  when 87..89 then 3.3
  when 83..86 then 3.0
  when 80..82 then 2.7
  when 77..79 then 2.3
  when 73..76 then 2.0
  when 70..72 then 1.7
  when 67..69 then 1.3
  when 63..66 then 1.0
  when 60..62 then 0.7
  else 0.0
  end
end