Jensen's Device: Difference between revisions

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@@ Line 171: / Line 171: @@
 i = Ref()
-def sum(ref_i, lo, hi, term):
+def sum(i, lo, hi, term):
    # term is passed by-name, and so is i
-   temp = 0;
+   temp = 0
-   for i in range(lo,hi+1):
+   i.value = lo
+   while i.value <= hi:          # Python has a for loop but it creates a distinct
-      ref_i.value = i
-      temp += term()
+      temp += term()             # variable which would not be shared with the passed i
+      i.value += 1
    return temp
 # note the correspondence between the mathematical notation and the call to sum