langs a-z

Task/Forward-difference/PL-I/forward-difference.pli

@@ -0,0 +1,21 @@
+/* Forward differences. */ /* 23 April 2010 */
+differences: procedure options (main);
+   declare a(10) fixed(10) static initial
+      (7, 3, 9, 250, 300, 4, 68, 72, 154, 601);
+   declare (i, j, m, n, t, u) fixed binary;
+
+   m = hbound(a,1);
+   get (n); if n > m then signal error;
+   put skip edit (a) (F(7));
+   do i = 1 to n;
+      t = a(i);
+      do j = i+1 to m;
+         u = a(j);
+         a(j) = a(j) - t;
+         t = u;
+      end;
+      put skip edit (a) (F(7));
+   end;
+   put skip edit ((a(i) do i = n+1 to m)) (F(9));
+
+end differences;