小甲鱼Python

P24 023递归：这帮小兔崽子

# def fab(n):#n1 = 1#n2 = 1#n3 = 1##if n < 1:# print('输入有误！')# return -1##while(n-2)>0:# n3 = n2 + n1# n1 = n2# n2 = n3# n -= 1###return n3## result = fab(20)# if result != -1:#print('共有%d 只兔崽子诞生'% result)def fab(n):if n < 1:print('输入有误')return -1if n ==1 or n==2:return 1else:return fab(n-1)+fab(n-2)result =fab(30)if result != -1:print('总共有%d只小兔崽子诞生'%result)