diff options
Diffstat (limited to 'var')
-rwxr-xr-x | var | 39 |
1 files changed, 39 insertions, 0 deletions
@@ -0,0 +1,39 @@ +#!/usr/bin/env ruby + +require 'trollop' + + +def usage + STDERR.write "./stddev [-r <d>] < <one number per line>\n" + exit 1 +end +usage if not [0,2].include? ARGV.size + +opts = Trollop::options do + opt :round, "Number of digits after decimal point.", :type => :int, :default => -1 +end + + +sum = 0.0 +i = 0 +cached = [] +while line=STDIN.gets + v = line.strip.to_f + sum += v + cached << v + i +=1 +end + +avg = sum/i.to_f + +var = 0 +cached.each { |v| + var += (avg - v)**2 +} + +if opts[:round] >= 0 + puts var.round opts[:round] +else + puts var +end + |