Sha256: 02d4571e99703f51e70546b7f3126ff0c5c96507cbc3642132cefb44f6c7947f
Contents?: true
Size: 770 Bytes
Versions: 9
Compression:
Stored size: 770 Bytes
Contents
describe Integer, "#harshad?" do
# http://www.research.att.com/~njas/sequences/A005349
HARSHAD = [1,2,3,4,5,6,7,8,9,10,12,18,20,21,24,27,30,36,40,
42,45,48,50,54,60,63,70,72,80,81,84,90,100,102,
108,110,111,112,114,117,120,126,132,133,135,140,
144,150,152,153,156,162,171,180,190,192,195,198,
200,201,204]
it "returns true for Harshad (Niven) numbers" do
HARSHAD.each do |number|
number.should be_harshad
end
end
it "returns false for non-Harshad/Niven numbers" do
((1..204).to_a - HARSHAD).each do |number|
number.should_not be_harshad
end
end
it "returns false for negative numbers" do
(1..204).each do |number|
(-number).should_not be_harshad
end
end
end
Version data entries
9 entries across 9 versions & 1 rubygems