Chapter 4-5. E seeking approximation (15 minutes)

Natural constant  e can stages  . 1 + . 1 / . 1 ! + . 1 / 2 ! + ⋯ + . 1 / n- ! + ⋯ be approximated. This problem requires a given non-negative integer  n, the number of stages required before the  n- + . 1 items and.

Input formats:

Input of the first row given non-negative integer   n-( ≤ . 1 0 0 0) .

Output formats:

Value output portion and in a row, eight decimal places.

Sample input:

10

 

Sample output:

2.71828180

 1 # 求e的近似值
 2 # Author: cnRick
 3 # Time  : 2020-3-28
 4 def factor(n):
 5     if n == 0:
 6         return 1.0
 7     result = 1.0
 8     for i in range(1,n+1):
 9         result *= i
10     return result
11 
12 n = int(input())
13 result = 0
14 for i in range(0,n+1):
15     result += 1/factor(i)
16 print("{:.8f}".format(result))