golang中循环或递归求阶乘

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

package main   import "fmt"   func factorialFor(num int) (ret int) {     // 循环求阶乘     ret = 1     for i := 1; i <= num; i++ {         ret *= i     }     return } func factorialRecursion(num int) int {     // 递归求阶乘     if num ==  0{         return 1     }     return num * factorialRecursion(num - 1) }   func main() {     // 循环求阶乘     ret := factorialFor(7)     fmt.Println(ret)     // 递归求阶乘     ret = factorialRecursion(7)     fmt.Println(ret)   }