Would this be possible?


#1

Would this work to find the mean average and the number of elements
greater than the average?

Calculating Avg and # of elements greater than Avg. in Ruby

sum = 0.0
n = 0
count = 0

while figure = STDIN.gets.to_f
sum += figure
n += 1
end

average = sum / n
puts “Average = #{average}”

while figure = STDIN.gets.to_f
if figure > average
count +=1
end
end

puts â??Number of elements greater than Avg = #{count}â?


#2

I’m not sure how that would work… you’re re-reading the input stream
twice.

Anyway, here’s my version. I could compact it more, but I won’t try
confusing you too much all at once. =)

figures = STDIN.read.split("\n").map { |x| x.to_f }

sum = figures.inject { |s, x| s + x }
average = sum / figures.size
high = figures.select { |x| x > average }

puts “Average: #{average}”
puts “Count greater than average: #{high.size}”


#3

There are a few problems.

  • Your input loop will never exit. On EOF STDIN.gets will return nil
    and then you call nil.to_f which is 0.0, which is a true value.

  • Your output needs new lines.

Consider


input = []
while a = STDIN.gets
input << a.to_f
end

average = input.inject(0) {|m,x| m = m+x} / input.size
count = input.count {|x| x > average}

print “Average = #{average}\n”
print “Number of elements greater than Avg = #{count}\n”


#4

Or even better:


input = STDIN.readlines.collect {|x| x.to_f}

average = input.inject(0) {|m,x| m = m+x} / input.size
count = input.count {|x| x > average}

print “Average = #{average}\n”
print “Number of elements greater than Avg = #{count}\n”