UPC: Difference between revisions

=={{header|Ruby}}==

{{trans|C}}

<lang ruby>DIGIT_F = {

" ## #" => 0,

" ## #" => 1,

" # ##" => 2,

" #### #" => 3,

" # ##" => 4,

" ## #" => 5,

" # ####" => 6,

" ### ##" => 7,

" ## ###" => 8,

" # ##" => 9,

}

DIGIT_R = {

"### # " => 0,

"## ## " => 1,

"## ## " => 2,

"# # " => 3,

"# ### " => 4,

"# ### " => 5,

"# # " => 6,

"# # " => 7,

"# # " => 8,

"### # " => 9,

}

END_SENTINEL = "# #"

MID_SENTINEL = " # # "

def decode_upc(s)

def decode_upc_impl(input)

upc = input.strip

if upc.length != 95 then

return false

end

pos = 0

digits = []

sum = 0

# end sentinel

if upc[pos .. pos + 2] == END_SENTINEL then

pos += 3

else

return false

end

# 6 left hand digits

for i in 0 .. 5

digit = DIGIT_F[upc[pos .. pos + 6]]

if digit == nil then

return false

else

digits.push(digit)

sum += digit * [1, 3][digits.length % 2]

pos += 7

end

end

# mid sentinel

if upc[pos .. pos + 4] == MID_SENTINEL then

pos += 5

else

return false

end

# 6 right hand digits

for i in 0 .. 5

digit = DIGIT_R[upc[pos .. pos + 6]]

if digit == nil then

return false

else

digits.push(digit)

sum += digit * [1, 3][digits.length % 2]

pos += 7

end

end

# end sentinel

if upc[pos .. pos + 2] == END_SENTINEL then

pos += 3

else

return false

end

if sum % 10 == 0 then

print digits, " "

return true

else

print "Failed Checksum "

return false

end

end

if decode_upc_impl(s) then

puts "Rightside Up"

elsif decode_upc_impl(s.reverse) then

puts "Upside Down"

else

puts "Invalid digit(s)"

end

end

def main

num = 0

print "%2d: " % [num += 1]

decode_upc(" # # # ## # ## # ## ### ## ### ## #### # # # ## ## # # ## ## ### # ## ## ### # # # ")

print "%2d: " % [num += 1]

decode_upc(" # # # ## ## # #### # # ## # ## # ## # # # ### # ### ## ## ### # # ### ### # # # ")

print "%2d: " % [num += 1]

decode_upc(" # # # # # ### # # # # # # # # # # ## # ## # ## # ## # # #### ### ## # # ")

print "%2d: " % [num += 1]

decode_upc(" # # ## ## ## ## # # # # ### # ## ## # # # ## ## # ### ## ## # # #### ## # # # ")

print "%2d: " % [num += 1]

decode_upc(" # # ### ## # ## ## ### ## # ## # # ## # # ### # ## ## # # ### # ## ## # # # ")

print "%2d: " % [num += 1]

decode_upc(" # # # # ## ## # # # # ## ## # # # # # #### # ## # #### #### # # ## # #### # # ")

print "%2d: " % [num += 1]

decode_upc(" # # # ## ## # # ## ## # ### ## ## # # # # # # # # ### # # ### # # # # # ")

print "%2d: " % [num += 1]

decode_upc(" # # # # ## ## # # ## ## ### # # # # # ### ## ## ### ## ### ### ## # ## ### ## # # ")

print "%2d: " % [num += 1]

decode_upc(" # # ### ## ## # # #### # ## # #### # #### # # # # # ### # # ### # # # ### # # # ")

print "%2d: " % [num += 1]

decode_upc(" # # # #### ## # #### # # ## ## ### #### # # # # ### # ### ### # # ### # # # ### # # ")

end

main()</lang>

{{out}}

<pre> 1: [9, 2, 4, 7, 7, 3, 2, 7, 1, 0, 1, 9] Rightside Up

2: [4, 0, 3, 9, 4, 4, 4, 4, 1, 0, 5, 0] Rightside Up

3: [8, 3, 4, 9, 9, 9, 6, 7, 6, 7, 0, 6] Upside Down

4: [9, 3, 9, 8, 2, 5, 1, 5, 8, 8, 1, 1] Upside Down

5: Invalid digit(s)

6: [3, 1, 6, 3, 1, 3, 7, 1, 8, 7, 1, 7] Upside Down

7: [2, 1, 4, 5, 7, 5, 8, 7, 5, 6, 0, 8] Rightside Up

8: [8, 1, 8, 7, 7, 8, 8, 4, 1, 8, 1, 3] Upside Down

9: [7, 0, 6, 4, 6, 6, 7, 4, 3, 0, 3, 0] Rightside Up

10: [6, 5, 3, 4, 8, 3, 5, 4, 0, 4, 3, 5] Rightside Up</pre>