作业

读程序，总结程序的功能:

1

numbers=1
for i in range(0,20):      
    numbers*=2  
print(numbers) 

此程序的功能是求2的20次方的值是多少

2

summation=0 
num=1 
while num<=100:    
    if (num%3==0 or num%7==0) and num%21!=0: 
         summation += 1
    num+=1 
print(summation)

求100以内能被3或者7整除，但不能被21整除的数的个数

编程实现(for和while各写⼀一遍):

1. 求1到100之间所有数的和、平均值

求和

num = 0
for i in range(1, 101):
    num += i
print(num)

num = 0
sum1 = 0
while num <= 100:
    sum1 += num
    num += 1

print(sum1)

求平均值

average = 0
num = 0
for i in range(1, 101):
    num += i
# print(num)
average = num
average /= i
print(average)


num = 0
sum1 = 0
average = 0
while num <= 100:
    sum1 += num
    num += 1
average = sum1
average /= num - 1

print(average)

2.计算1-100之间能3整除的数的和

sum1 = 0
for num in range(1,100):
    if num % 3 == 0:
        sum1 += num
print(sum1)


sum2 = 0
num = 0
while num < 100:
    if num % 3 == 0:
        sum2 += num
    num += 1
print(sum2)

3.计算1-100之间不能被7整除的数的和

sum1 = 0
for num in range(1, 100):
    if num % 7 != 0:
        sum1 += num
print(sum1)


sum2 = 0
num = 0
while num < 100:
    if num % 7 != 0:
        sum2 += num
    num += 1
print(sum2)

1. 求斐波那契数列列中第n个数的值：1，1，2，3，5，8，13，21，34....

n = int(input("请输入一个整数:"))
a = 1
b = 1
num = 0
for i in range(n-2):
    # print(a,end=" ")
    num = a + b
    a = b
    b = num
    # print(a, end=" ")
print("第%d数是%d:" % (n, num))

2. 判断101-200之间有多少个素数，并输出所有素数。判断素数的⽅方法：⽤用⼀一个数分别除2到sqrt(这个 数)，如果能被整除，则表明此数不不是素数，反之是素数

import math
for i in range(101,201):
    a = 2
    while a < i:
        if i % a == 0:
            break
        else:
            a = a + 1
    if a >= math.sqrt(i):
            print("%d是素数" % i)

3. 打印出所有的水仙花数,所谓水仙花数是指一个三位数，其各位数字⽴方和等于该数本身。例例如：153是 一个水仙花数,因为153 = 1^3 + 5^3 + 3^3

for n in range(100, 1000):
   h = n // 100
   t = n % 100 // 10
   b = n % 10
   if h**3 + t**3 + b**3 != n:
       n = n + 1
   else:
       print("%d是水仙花数" % n)

4.有⼀分数序列列：2/1,3/2,5/3,8/5,13/8,21/13...求出这个数列的第20个分数 分子：上一个分数的分子加分母 分母: 上一个分数的分子 fz = 2 fm = 1 fz+fm / fz

number = 20
a = 2
b = 1
t = 0
for i in range(1, number + 1):
    
    t = a
    a = a + b
    b = t

print(t)

5. 给⼀一个正整数，要求：1、求它是几位数 2.逆序打印出各位数字

while True:
    num = int(input("请输入一个任意整数:"))
    i = 0
    n = 0
    a = num
    while a >= 1:
        a = a // 10
        n = n + 1
    

    num1 = num
    while True:
        if num1 // 10 == 0:
            break
        i += 1
        num1 = num1 // 10
    sum = 0
    while i >= 0:
        sum = sum + (num % 10) * (10 ** i)
        num = num // 10
        i = i - 1
    print("num是%d位数" % n,  sum)