package main
import "fmt"
var facVal uint64 = 1
var i int = 1
var n int
/* function declaration */
func factorial(n int) uint64 {
if n < 0 {
fmt.Print("Factorial of negative number doesn't exist.")
} else {
for i := 1; i <= n ; i++ {
facVal *= uint64(i)
}
}
return facVal
}
func main() {
fmt.Println("Enter a positive integer between 0 - 50 : ")
fmt.Scan(&n)
fmt.Print("Factorial is: ", factorial(n))
}
