Calculates grades and can sort students based on any field.

grades_and_sort.rb

Struct.new("Student", :scores, :first_name, :last_name, :ssn)

class AverageScores

  attr_accessor :scores

  def initialize(scores)
    @scores = scores
  end

  def basic_average
    scores.inject{|total,grade| total + grade }/ scores.count
  end

  def letter_grade
    case basic_average
      when 90..100
        "A"
      when 80..89
        "B"
      when 70..79
        "C"
      when 60..69
        "D"
      else
        "F"
      end
  end

end

class LinearSearch

  NORESULT = "No Results Found"

  attr_accessor :data, :query, :field

  def initialize(data, field, query)
    @data = data
    @field = field
    @query = query
  end

  def search
    all_positions = []
    data.each_with_index do |info,index|
      if info[field] == query
        all_positions << index
      end
    end
    all_positions.empty? ? NORESULT : all_positions
  end

end

class BinarySearch

 NORESULT = "No Results Found"

  attr_accessor :data, :query, :field

  def initialize(data, field, query)
    @data = data
    @field = field
    @query = query
  end

  def search(data_info = data)
    if  data_info.empty?
      NORESULT
    else
    mid = data_info.count/2 - 1
    return data_info.first.values if data_info.first[field] == query
      if data_info.at(mid).ssn < query
        data_info.slice!(1..mid)
        search(data_info)
      elsif data_info.at(mid).ssn > query
        data_info.slice!(mid..-1)
        search(data_info)
      end
    end
  end

end

class Sort

  attr_accessor :data, :field

  def initialize(data, field)
    @data = data
    @field = field
  end

  def sort_it
    data.sort_by{|x| x[field] }
  end

end


  students = [Struct::Student.new([100,100,100,0,100],"Alex", "Trebek", "111-11-111")]
  
  4.times do 
    students << Struct::Student.new([100,100,100,0,100],"Bob", "Ee", "100-12-121")
  end
  
  students << Struct::Student.new([100,100,100,0,100],"Alex", "Smith", "123-12-142")

  p students[0].first_name == "Alex"
  p students[0].scores.length == 5
  p students[0].scores[0] == students[0].scores[4]
  p students[0].scores[3] == 0
  p AverageScores.new(students[0].scores).basic_average == 80
  p AverageScores.new(students[0].scores).letter_grade == 'B'
  p LinearSearch.new(students, "first_name", "Alex").search == [0,5]
  p LinearSearch.new(students, "first_name", "NOT A STUDENT").search== "No Results Found"
  
  Sort.new(students, "ssn").sort_it
  p students[0].ssn > students[1].ssn
  p students[5].ssn > students[0].ssn
  
  p BinarySearch.new(students, "ssn", "111-11-111").search
  p BinarySearch.new(students, "ssn", "111-11-111").search == [[100, 100, 100, 0, 100], "Alex", "Trebek", "111-11-111"]
  p BinarySearch.new(students, "ssn", "000-00-0000").search
  p BinarySearch.new(students, "ssn", "000-00-0000").search == "No Results Found"