2016 Update

Task/Remove-duplicate-elements/ALGOL-68/remove-duplicate-elements-1.alg

@@ -0,0 +1,31 @@
+# use the associative array in the Associate array/iteration task    #
+# this example uses strings - for other types, the associative       #
+# array modes AAELEMENT and AAKEY should be modified as required     #
+PR read "aArray.a68" PR
+
+# returns the unique elements of list                                #
+PROC remove duplicates = ( []STRING list )[]STRING:
+     BEGIN
+        REF AARRAY elements := INIT LOC AARRAY;
+        INT        count    := 0;
+        FOR pos FROM LWB list TO UPB list DO
+            IF NOT ( elements CONTAINSKEY list[ pos ] ) THEN
+                # first occurance of this element                    #
+                elements // list[ pos ] := "";
+                count +:= 1
+            FI
+        OD;
+        # construct an array of the unique elements from the         #
+        # associative array - the new list will not necessarily be   #
+        # in the original order                                      #
+        [ count ]STRING result;
+        REF AAELEMENT e := FIRST elements;
+        FOR pos WHILE e ISNT nil element DO
+            result[ pos ] := key OF e;
+            e := NEXT elements
+        OD;
+        result
+     END; # remove duplicates #
+
+# test the duplicate removal                                         #
+print( ( remove duplicates( ( "A", "B", "D", "A", "C", "F", "F", "A" ) ), newline ) )

Task/Remove-duplicate-elements/ALGOL-68/remove-duplicate-elements-2.alg

@@ -0,0 +1,2 @@
+∪ 1 2 3 1 2 3 4 1
+1 2 3 4

Task/Remove-duplicate-elements/ALGOL-68/remove-duplicate-elements-3.alg

@@ -0,0 +1,3 @@
+w←1 2 3 1 2 3 4 1
+     ((⍳⍨w)=⍳⍴w)/w
+1 2 3 4