How do I print binary, octal and hexadecimal numeric values in their declared form?-CodePudding

I'm declaring the following constants and printing their values, but when I print they always print in their decimal form. How do I get them to print in their originally defined form?

let binaryInteger = 0b10001
let octalInteger = 0o21
let hexadecimalInteger = 0x11
print("Binary Integer: \(binaryInteger) and in binary \(binaryInteger)")
print("Octal Integer: \(octalInteger) and in octal \(octalInteger)")
print("Hexadecimal Integer: \(hexadecimalInteger) and in hexadecimal \(hexadecimalInteger)")

The output I'd like to see for the first print statement would be:

Binary Integer: 17 and in binary 10001.

What do I need to put in front of the \( to get it to print in binary/octal/hex?

CodePudding user response：

You have to convert the integers to given String representation manually:

print("Binary Integer: \(binaryInteger) and in binary \(String(binaryInteger, radix: 2))")
print("Octal Integer: \(octalInteger) and in octal \(String(octalInteger, radix: 8))")
print("Hexadecimal Integer: \(hexadecimalInteger) and in hexadecimal \(String(hexadecimalInteger, radix: 16))")

Of course, you might also create custom String interpolation to be able to use something like the following:

print("Hexadecimal Integer: \(hexadecimalInteger) and in hexadecimal \(hexadecimalInteger, radix: 16)")

See an example here

CodePudding user response：

Basic answer is given by Silthan, I would also wrap it in the structure, which helps to preserve the original format:

enum Radix: Int {
    
    case binary = 2
    case octal = 8
    case hexa = 16
    
    var prefix: String {
        switch self {
        case .binary:
            return "0b"
        case .octal:
            return "0o"
        case .hexa:
            return "0x"
        }
    }
}

struct PresentableNumber<T> where T: BinaryInteger & CustomStringConvertible {
    
    let number: T
    let radix: Radix
    
    var originalPresentation: String {
        return radix.prefix   String(number, radix: radix.rawValue)
    }
}

extension PresentableNumber: CustomStringConvertible {
    
    var description: String {
        return number.description
    }
}

This way you can define and print your numbers like this:

let binaryInteger = PresentableNumber(number: 0b10001, radix: .binary)
let octalInteger = PresentableNumber(number: 0o21, radix: .octal)
let hexadecimalInteger = PresentableNumber(number: 0x11, radix: .hexa)

print("Binary Integer: \(binaryInteger) and in binary \(binaryInteger.originalPresentation)")
print("Octal Integer: \(octalInteger) and in octal \(octalInteger.originalPresentation)")
print("Hexadecimal Integer: \(hexadecimalInteger) and in hexadecimal \(hexadecimalInteger.originalPresentation)")

The output:

Binary Integer: 17 and in binary 0b10001
Octal Integer: 17 and in octal 0o21
Hexadecimal Integer: 17 and in hexadecimal 0x11