Currency: Difference between revisions

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@@ Line 1,422: / Line 1,422: @@
 =={{header|OCaml}}==
-Using the [https://github.com/janestreet/bignum Bignum] library.
+Using the [https://ocaml.org/p/decimal/0.3.0 decimal] library.
-<syntaxhighlight lang="ocaml">#require "bignum" ;;
+<syntaxhighlight lang="ocaml">
+let () =
+  let open Decimal in (* bring all functions and operators into scope locally *)
+  let s = of_string in
+  let i = of_int in
-let p1 = Bignum.((of_string "4000000000000000") * (of_float_decimal 5.50)) ;;
+  let hamburgers = s "4e15" * s "5.50" in
-let p2 = Bignum.((of_int 2) * (of_float_decimal 2.86)) ;;
+  let milkshakes = i 2 * s "2.86" in
+  let tax_rate = s "7.65e-2" in
+  let subtotal = hamburgers + milkshakes in
+  let tax = subtotal * tax_rate in
+  let total = subtotal + tax in
+  Printf.printf
-let r1 = Bignum.(p1 + p2) ;;
+    "Subtotal: %20s
-let r2 = Bignum.(r1 * (of_float_decimal (7.65 /. 100.))) ;;
+     Tax: %20s
-let r3 = Bignum.(r1 + r2) ;;
+   Total: %20s\n"
+    (to_string (round ~n:2 subtotal))
-let my_to_string v =
+    (to_string (round ~n:2 tax))
-  Bignum.(v |> round_decimal ~dir:`Nearest ~digits:2
+    (to_string (round ~n:2 total))
-            |> to_string_hum ~decimals:2) ;;
+</syntaxhighlight>
-let () =
-  Printf.printf "before tax: %s\n" (my_to_string r1);
-  Printf.printf "tax:        %s\n" (my_to_string r2);
-  Printf.printf "total:      %s\n" (my_to_string r3);
-;;</syntaxhighlight>
 {{out}}
 <pre>
+Subtotal: 22000000000000005.72
-$ opam install bignum
+     Tax:  1683000000000000.44
-$ opam install utop
+   Total: 23683000000000006.16
-$ eval $(opam env)
-$ utop currency.ml
-before tax: 22000000000000005.72
-tax:        1683000000000000.44
-total:      23683000000000006.16
 </pre>