典型循环:s=1!+2!+3!+……+n!,用三种循环编程

1. for循环

n = int(input("请输入一个正整数："))
s = 0
for i in range(1, n+1):
    fac = 1
    for j in range(1, i+1):
        fac *= j
    s += fac
print("s =", s)

2. while循环

n = int(input("请输入一个正整数："))
s = 0
i = 1
while i <= n:
    fac = 1
    j = 1
    while j <= i:
        fac *= j
        j += 1
    s += fac
    i += 1
print("s =", s)

3. do-while循环

n = int(input("请输入一个正整数："))
s = 0
i = 1
while True:
    fac = 1
    j = 1
    while j <= i:
        fac *= j
        j += 1
    s += fac
    i += 1
    if i > n:
        break
print("s =", s)