Negative base numbers: Difference between revisions

=={{header|Wren}}==

{{trans|Kotlin}}

{{libheader|Wren-fmt}}

<lang ecmascript>import "/fmt" for Fmt

var digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"

var encodeNegBase = Fn.new { |n, b|

if (b < -62 || b > -1) Fiber.abort("Base must be between -1 and -62")

if (n == 0) return "0"

var out = ""

while (n != 0) {

var rem = n % b

n = (n/b).truncate

if (rem < 0) {

n = n + 1

rem = rem -b

}

out = out + digits[rem]

}

return out[-1..0]

}

var decodeNegBase = Fn.new { |ns, b|

if (b < -62 || b > -1) Fiber.abort("Base must be between -1 and -62")

if (ns == "0") return 0

var total = 0

var bb = 1

for (c in ns[-1..0]) {

total = total + digits.indexOf(c)*bb

bb = bb * b

}

return total

}

var nbl = [ [10, -2], [146, -3], [15, -10], [-7425195, -62] ]

for (p in nbl) {

var ns = encodeNegBase.call(p[0], p[1])

Fmt.print("$8d encoded in base $-3d = $s", p[0], p[1], ns)

var n = decodeNegBase.call(ns, p[1])

Fmt.print("$8s decoded in base $-3d = $d\n", ns, p[1], n)

}</lang>

{{out}}

<pre>

10 encoded in base -2 = 11110

11110 decoded in base -2 = 10

146 encoded in base -3 = 21102

21102 decoded in base -3 = 146

15 encoded in base -10 = 195

195 decoded in base -10 = 15

-7425195 encoded in base -62 = Wren

Wren decoded in base -62 = -7425195

</pre>