Data update

Task/Fibonacci-sequence/Pascal/fibonacci-sequence-6.pas

@@ -1,62 +1,18 @@
-program Fibonacci_console;
-
-{$mode objfpc}{$H+}
-
-uses SysUtils;
-
-function Fibonacci( n : word) : uint64;
-{
-Starts with the pair F[0],F[1]. At each iteration, uses the doubling formulae
-to pass from F[k],F[k+1] to F[2k],F[2k+1]. If the current bit of n (starting
-from the high end) is 1, there is a further step to F[2k+1],F[2k+2].
-}
-var
-  marker, half_n : word;
-  f, g : uint64; // pair of consecutive Fibonacci numbers
-  t, u : uint64; // -----"-----
-begin
-  // The values of F[0], F[1], F[2]  are assumed to be known
-  case n of
-    0 : result := 0;
-    1, 2 : result := 1;
-    else begin
-      half_n := n shr 1;
-      marker := 1;
-      while marker <= half_n do marker := marker shl 1;
-
-      // First time: current bit is 1 by construction,
-      //   so go straight from F[0],F[1] to F[1],F[2].
-      f := 1; // = F[1]
-      g := 1; // = F[2]
-      marker := marker shr 1;
-
-      while marker > 1 do begin
-        t := f*(2*g - f);
-        u := f*f + g*g;
-        if (n and marker = 0) then begin
-          f := t;
-          g := u;
-        end
-        else begin
-          f := u;
-          g := t + u;
-        end;
-        marker := marker shr 1;
-      end;
-
-      // Last time: we need only one of the pair.
-      if (n and marker = 0) then
-        result := f*(2*g - f)
-      else
-        result := f*f + g*g;
-    end; // end else (i.e. n > 2)
-  end; // end case
-end;
-
-// Main program
-var
-  n : word;
-begin
-  for n := 0 to 93 do
-    WriteLn( SysUtils.Format( 'F[%2u] = %20u', [n, Fibonacci(n)]));
-end.
+function Fibo_BigInt(n: integer): string;  //maXbox
+  var tbig1, tbig2, tbig3: TInteger;
+  begin
+    result:= '0'
+    tbig1:= TInteger.create(1);  //temp
+    tbig2:= TInteger.create(0);  //result (a)
+    tbig3:= Tinteger.create(1);  //b
+    for it:= 1 to n do begin
+    	tbig1.assign(tbig2)
+	   tbig2.assign(tbig3);
+	   tbig1.add(tbig3);
+	   tbig3.assign(tbig1);
+	 end;
+    result:= tbig2.toString(false)
+    tbig3.free;
+    tbig2.free;
+    tbig1.free;
+  end;