import Foundation
/// Namespace for cryptographically secure 8-digit number and code utilities.
public enum RandomCodeGenerator {
// Numeric constants with underscore separators for visual clarity
private static let min8DigitInt: Int = 10_000_000
private static let max8DigitInt: Int = 99_999_999
private static let maxCodeValue: Int = 99_999_999
/// Generates a cryptographically secure 8-digit positive integer between 10,000,000 and 99,999,999 (inclusive).
/// Guaranteed to start with a non-zero digit (1–9).
///
/// - Returns: An 8-digit `Int`.
public static func generate8DigitNumber() -> Int {
// Swift's native Int.random(in:) accepts ClosedRange (a...b) natively
// and uses the system's cryptographically secure PRNG automatically.
return Int.random(in: min8DigitInt...max8DigitInt)
}
/// Generates an 8-character numeric string code between "00000000" and "99999999".
/// Preserves leading zeros using String format specifiers, making it suitable for OTPs, PINs, or tokens.
///
/// - Returns: An 8-character numeric `String` padded with leading zeros if necessary.
public static func generate8DigitCode() -> String {
let rawValue = Int.random(in: 0...maxCodeValue)
// String(format: "%08d", ...) formats the integer with a minimum width of 8,
// padding shorter values with leading zeros.
return String(format: "%08d", rawValue)
}
}
// ==========================================
// Example Execution
// ==========================================
func main() {
print("=== Generating 8-Digit Integers [10000000 to 99999999] ===")
for index in 1...3 {
let randomNumber = RandomCodeGenerator.generate8DigitNumber()
print("Generated integer #\(index): \(randomNumber)")
}
print("\n=== Generating 8-Digit String Codes [00000000 to 99999999] ===")
for index in 1...3 {
let randomCode = RandomCodeGenerator.generate8DigitCode()
print("Generated OTP code #\(index): \(randomCode)")
}
}
// Execute program main
main()
/*
run:
=== Generating 8-Digit Integers [10000000 to 99999999] ===
Generated integer #1: 27803289
Generated integer #2: 64060177
Generated integer #3: 13393335
=== Generating 8-Digit String Codes [00000000 to 99999999] ===
Generated OTP code #1: 50315579
Generated OTP code #2: 19819077
Generated OTP code #3: 15774851
*/
