langs a-z

Task/Pi/Pascal/pi.pascal

@@ -0,0 +1,51 @@
+Program Pi_Spigot;
+
+const
+  n   = 1000;
+  len = 10*n div 3;
+
+var
+  i, j, k, q, x, nines, predigit: integer;
+  a: array[1..len] of longint;
+
+begin
+  for j := 1 to len do
+    a[j] := 2;                 {Start with 2s}
+  nines := 0;
+  predigit := 0;               {First predigit is a 0}
+  for j := 1 to n do
+  begin
+    q := 0;
+    for i := len downto 1 do   {Work backwards}
+    begin
+      x    := 10*a[i] + q*i;
+      a[i] := x mod (2*i - 1);
+      q    := x div (2*i - 1);
+    end;
+    a[1] := q mod 10;
+    q := q div 10;
+    if q = 9 then
+      nines := nines + 1
+    else
+      if q = 10 then
+      begin
+	write(predigit+1);
+	for k := 1 to nines do
+	  write(0);            {zeros}
+	predigit := 0;
+	nines := 0
+      end
+      else
+      begin
+	write(predigit);
+	predigit := q;
+	if nines <> 0 then
+	begin
+	  for k := 1 to nines do
+	    write(9);
+	  nines := 0
+	end
+      end
+  end;
+  writeln(predigit);
+end.