Knapsack problem/Continuous: Difference between revisions

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 =={{header|ooRexx}}==
+===version 1===
 <lang oorexx>/*--------------------------------------------------------------------
 * 20.09.2014 Walter Pachl translated from REXX version 2
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 -----------------------
 total    15.000 349.378</pre>
+===version 2===
+<lang oorexx>/*--------------------------------------------------------------------
+* 20.09.2014 Walter Pachl translated from REXX version 2
+*            utilizing ooRexx features like objects, array(s) and sort
+* 21.09.2014 simplified (courtesy Rony Flatscher)
+*            (sort uses now the methos defined for item)
+*-------------------------------------------------------------------*/
+  maxweight = 15.0
+  items=.array~new
+  items~append(.item~new('beef',    3.8, 36.0))
+  items~append(.item~new('pork',    5.4, 43.0))
+  items~append(.item~new('ham',     3.6, 90.0))
+  items~append(.item~new('greaves', 2.4, 45.0))
+  items~append(.item~new('flitch',  4.0, 30.0))
+  items~append(.item~new('brawn',   2.5, 56.0))
+  items~append(.item~new('welt',    3.7, 67.0))
+  items~append(.item~new('salami',  3.0, 95.0))
+  items~append(.item~new('sausage', 5.9, 98.0))
+  /* show the input */
+  Say '#    vpu name    weight   value'
+  i=0
+  Do x over items
+    i+=1
+    Say i format(x~vpu,2,3) left(x~name,7) format(x~weight,2,3) format(x~value,3,3)
+    End
+  /* sort the items by descending value per unit of weight */
+  items~sort          /* using the method compareTo used for item */
+  total_weight=0
+  total_value =0
+  Say ' '
+  Say 'Item     Weight   Value'
+  i=0
+  Do x over items
+    i+=1
+    Parse Var item.i name '*' weight '*' value
+    if total_weight+x~weight<maxweight then Do
+      total_weight = total_weight + x~weight
+      total_value  = total_value + x~value
+      Say left(x~name,7) format(x~weight,3,3) format(x~value,3,3)
+      End
+    Else Do
+      weight=maxweight-total_weight
+      value=weight*x~vpu
+      total_value = total_value + value
+      total_weight = maxweight
+      Say left(x~name,7) format(weight,3,3) format(value,3,3)
+      Leave
+      End
+    End
+  Say copies('-',23)
+  Say 'total ' format(total_weight,4,3) format(total_value,3,3)
+  Exit
+::class item
+  ::attribute vpu
+  ::attribute name
+  ::attribute weight
+  ::attribute value
+::method init
+  Expose vpu
+  Use Arg name, weight, value
+  self~name=name
+  self~weight=weight
+  self~value=value
+  self~vpu=value/weight
+::method compareTo   -- default sort order
+  Expose vpu
+  use Arg other
+  return -sign(vpu - other~vpu)</lang>
+Output is the same as for version 1.
 =={{header|Perl}}==