CUSIP: Difference between revisions

=={{header|Swift}}==

<lang swift>struct CUSIP {

var value: String

private static let alphabet = Array("ABCDEFGHIJKLMNOPQRSTUVWXYZ")

init?(value: String) {

if value.count == 9 && String(value.last!) == CUSIP.checkDigit(cusipString: String(value.dropLast())) {

self.value = value

} else if value.count == 8, let checkDigit = CUSIP.checkDigit(cusipString: value) {

self.value = value + checkDigit

} else {

return nil

}

}

static func checkDigit(cusipString: String) -> String? {

guard cusipString.count == 8, cusipString.allSatisfy({ $0.isASCII }) else {

return nil

}

let sum = cusipString.uppercased().enumerated().reduce(0, {sum, pair in

let (i, char) = pair

var v: Int

switch char {

case "*":

v = 36

case "@":

v = 37

case "#":

v = 38

case _ where char.isNumber:

v = char.wholeNumberValue!

case _:

v = Int(char.asciiValue! - 65) + 10

}

if i & 1 == 1 {

v *= 2

}

return sum + (v / 10) + (v % 10)

})

return String((10 - (sum % 10)) % 10)

}

}

let testCases = [

"037833100",

"17275R102",

"38259P508",

"594918104",

"68389X106",

"68389X105"

]

for potentialCUSIP in testCases {

print("\(potentialCUSIP) -> ", terminator: "")

switch CUSIP(value: potentialCUSIP) {

case nil:

print("Invalid")

case _:

print("Valid")

}

}</lang>

{{out}}

<pre>037833100 -> Valid

17275R102 -> Valid

38259P508 -> Valid

594918104 -> Valid

68389X106 -> Invalid

68389X105 -> Valid</pre>