基础

读程序，总结程序的功能:

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

功能:求2的20次方

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)

功能:求出100以内3和21的倍数，7和21的倍数，他们的倍数和

编程实现(for和while各写一遍):

1. 求1到100之间所有数的和、平均值

sum1 = 0
for num in range(1, 101):
    sum1+=num
print(sum1)
print(sum1/num)
5050
50.5


n=1
sum2=0
while n<=100:
    sum2+=n
    n+=1
print(sum2)
print(sum2/n)
5050
50.5

2. 计算1-100之间能3整除的数的和

sum1 = 0
for num in range(100):
   if num%3==0:
     sum1+=num
print(sum1)
1683


n=1
sum1=0
while n<=100:
   if n%3==0:
       sum1+=n
       if n==100:
           break
   n+=1
print(sum1)
1683

3. 计算1-100之间不能被7整除的数的和

sum1 = 0
for num in range(1,101):
   if num%7!=0:
     sum1+=num
print(sum1)
4315


n=1
sum1=0
while n<=100:
    if not (n%7)==0:
        sum1+=n
    if n==100:
           break
    n+=1
print(sum1)
4315