// fact.swift  compute factorials

#if os(OSX) || os(iOS) // for libraries, portable for OSX and Linux
import Foundation
#elseif os(Linux)
import Glibc
#endif// 

print("fact.swift running  overflow for n at 21")

func fact(n: Int) -> Int {
  if n<=1 {
    return 1
  }
  return n*fact(n:n-1)
}

var nfact = 0
for n in 0...20 { 
 nfact = fact(n:n)
 print("fact(\(n)) = \(nfact)")
}

print("\n fact.swift finished")