Question

a ruby program problem

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Ruby These short language exercises are intended to help you to explore new languages with differing paradigms and syntax. In this assignment you will complete a Ruby program. I will give you help on where and what to look for in Ruby to assist you. Write a Ruby program to solve the following problem: Open a file that has a list of scores between 0 and 100. There may be as many as 100 scores in the file. The file is plain text and each score is on a separate line. Count the number of each score you find from 0 to 100. After you have counted all the scores, then print out a histogram using 10 buckets of size 10, that is, 0-9, 10-19,..., and 90-100. Then the histogram will print a for each score in the bucket. Example output Count17, Average 72.00, StdDev-15.07 0 . 10 . 20. 30. 40. 50 . 60 . 70 . 80.90.100 The input file scores.txt for this output looks like this 85 72 63 65 92 78 71 73 85 87 29 79 89 72 67 So, you read one score per line. Now you must use Ruby objects to solve this problem (you can do it without but solving the problem is not the point of this exercise). Create a class Histogram with the following methods: initialize(lowScore, hiscore, bucketsize) addScores (file) addScore(score) print

Answer 1

compute.rb

# Note I have changed the name of the function "print" to "prints" because I have used

# ruby's print function inside prints function.

class Histogram

@lowScore # lowest possible Score in scores

@hiScore # highest possible score in scores

@bucketSize # size of each bucket

@count # count of each bucket

@Count # number of scores

@Average # average of scores

@StdDev # standard deviation of scores

def initialize(lowScore=0,hiScore=100,bucketSize=10) # initializer function

@lowScore = lowScore

@hiScore = hiScore

@bucketSize = bucketSize

@count = Array.new((hiScore-lowScore)/bucketSize){0}

@Count = 0

end

def addScores(file) # add Score function

total = 0

File.open("scores.txt").each do |score|

addScore(score.to_i) # count of each bucket

@Count += 1 # count of the number of scores

total += score.to_i # sum of scores

end

@Average = total.to_f/@Count # average of score

tmp = 0

File.open("scores.txt").each do |score|

tmp += ((score.to_i-@Average)**2/@Count.to_f)

end

@StdDev = tmp**0.5 # standard deviation of score

end

def addScore(score) # fnction to increament the count of each bucket

i = (score-@lowScore)/@bucketSize

@count[i] += 1

end

def prints # function to print

max = @count.max

puts "Count = %s, Average = %s, StdDev = %s"%[@Count,@Average.round(2),@StdDev.round(2)]

while max>0

for s in @count

if s>=max

print "%3s%1s"%["*"," "]

else

print "%4s"%[" "]

end

end

puts ""

max = max -1

end

i = @lowScore

while i<@hiScore

print "%3s%1s"%[i,"."]

i = i+@bucketSize

end

print @hiScore

end

end

h = Histogram.new

h.addScores("scores.txt")

h.prints