Three word location: Difference between revisions

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@@ Line 225: / Line 225: @@
 </pre>
-=== Idiomatic version ===
+=== Idiomatic version with scrambling===
+<lang julia>using Random
-Output is the same as direct translation version.
-<lang julia>
 const LAT = 28.3852
 const LON = -81.5638
@@ Line 234: / Line 234: @@
 const wordarray = ["W" * string(x, pad=5) for x in 0:28125]
-function threewordencode(lat, lon) # returns vector of 3 strings
+function threewordencode(lat, lon, seed=0) # returns vector of 3 strings
+    arr = wordarray
+    if seed != 0
+        rng = MersenneTwister(seed)
+        arr = shuffle(rng, deepcopy(wordarray))
+    end
     i = (Int(lat * 10000 + 900000) << 22) | Int(lon * 10000 + 1800000)
-    return map(x -> wordarray[x + 1], [(i >> 28) & 0xefff, (i >> 14) & 0x7fff, i & 0x7fff])
+    return map(x -> arr[x + 1], [(i >> 28) & 0xefff, (i >> 14) & 0x7fff, i & 0x7fff])
 end
+function threeworddecode(w1, w2, w3, seed=0) # returns pair of Float64
-words = threewordencode(LAT, LON)
+    arr = wordarray
-println(join(words, " "))
+    if seed != 0
+        rng = MersenneTwister(seed)
-function threeworddecode(w1, w2, w3) # returns pair of Float64
-    (i1, i2, i3) = indexin([w1, w2, w3], wordarray) .- 1
+        arr = shuffle(rng, deepcopy(wordarray))
+    end
+    (i1, i2, i3) = indexin([w1, w2, w3], arr) .- 1
     latlon = (i1 << 28) | (i2 << 14) | i3
     ilon, ilat = latlon & 0xfffff, latlon >> 22
     return  (ilon - 1800000) / 10000, (ilat - 900000) / 10000
 end
+words = threewordencode(LAT, LON)
+println(join(words, " "))
 lat, lon = threeworddecode(words...)
 println("latitude = $lat longitude = $lon")
-</lang>
+println("\nWith scramble using key 12345678:")
+words = threewordencode(LAT, LON, 12345678)
+println(join(words, " "))
+lat, lon = threeworddecode(words..., 12345678)
+println("latitude = $lat longitude = $lon")
+</lang>{{out}}
+<pre>
+W18497 W27708 W01322
+latitude = -81.5638 longitude = 28.3852
+With scramble using key 12345678:
+W20242 W23427 W16215
+latitude = -81.5638 longitude = 28.3852
+</pre>
 =={{header|Symsyn}}==