All,

Would someone try the below unit test and explain why ruby does not

pass. It came up while I was trying to write a generalized rounding

method for floats that takes the number of place to round to as a

parameter. It gave wrong answers, but only on rare inputs.

For example, (9.245 * 100).round should be 925, but my ruby gives 924.

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#! /usr/bin/env ruby

require ‘test/unit’

class TestFloatRounding < Test::Unit::TestCase

def test_round

assert_equal(925, 924.5.round, “Rounding Error: 924.5.round”)

assert_equal(9.25, (9.245 * 10.0**2).round / 10.0**2, “Rounding

Error: (9.245 * 10.0**2).round / 10.0**2”)

assert_equal(925, (9.245 * 10.0**2).round, "Rounding Error:(9.245

- 10.0
**2).round")**2, “Rounding Error: 9.245 *

assert_equal(924.5, 9.245 * 10.0

10.0**2”)

assert_equal(925, 924.5.round, “Rounding Error: 924.5.round”)

assert_equal(924.5, 9.245 * 10 * 10, “Rounding Error: 9.245 * 10 *

10”)

assert_equal(925, (9.245 * 10 * 10).round, "Rounding Error: (9.245 - 10 * 10).round")

assert_equal(925.0, 9.245 * 10 * 10 + 0.5, "Rounding Error: 9.245 - 10 * 10 + 0.5")

assert_equal(925, (9.245 * 10 * 10 + 0.5).floor, “Rounding Error:

(9.245 * 10 * 10 + 0.5).floor”)

end

end

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