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--
-- Project Euler problem #8
--
-- Find the greatest product of five consecutive digits in the 1000-digit
-- number.
with Ada.Text_IO;
use Ada.Text_IO;
procedure Eight is
Source : constant String := "73167176531330624919225119674426574742355349194934" &
"96983520312774506326239578318016984801869478851843" &
"85861560789112949495459501737958331952853208805511" &
"12540698747158523863050715693290963295227443043557" &
"66896648950445244523161731856403098711121722383113" &
"62229893423380308135336276614282806444486645238749" &
"30358907296290491560440772390713810515859307960866" &
"70172427121883998797908792274921901699720888093776" &
"65727333001053367881220235421809751254540594752243" &
"52584907711670556013604839586446706324415722155397" &
"53697817977846174064955149290862569321978468622482" &
"83972241375657056057490261407972968652414535100474" &
"82166370484403199890008895243450658541227588666881" &
"16427171479924442928230863465674813919123162824586" &
"17866458359124566529476545682848912883142607690042" &
"24219022671055626321111109370544217506941658960408" &
"07198403850962455444362981230987879927244284909188" &
"84580156166097919133875499200524063689912560717606" &
"05886116467109405077541002256983155200055935729725" &
"71636269561882670428252483600823257530420752963450";
function Digits_Product (Input : in String) return Natural is
Result : Natural := 1;
begin
for Item in Input'Range loop
Result := (Result * Natural'Value (Input (Item .. Item)));
end loop;
return Result;
end Digits_Product;
Highest : Natural := 0;
begin
for Index in 1 .. (Source'Length - 5) loop
declare
Sub : constant String := Source (Index .. Index + 4);
Product : constant Natural := Digits_Product (Sub);
begin
if Product > Highest then
Highest := Product;
end if;
end;
end loop;
Put_Line ("> Highest product:" & Natural'Image (Highest));
end Eight;