day4homework

读程序，总结程序的功能：

1.打印一个数连续乘以2二十次

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

2.判断一个数是否能够被3或7整除，但是不能被21整除

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)

编程实现(for和while各写一遍)

1.求1打100之间所有数的和、平均值

sum1 = 0    
for num in range(1,101):
    sum1 += num
print(sum1,sum1/100)

num2 = 0
num3 = 0
while  num3 <= 100:
    num2 += num3
    num3 += 1
print(num2,num2/100)

2. 计算1-100之间能3整除的数的和

sum2 = 0
x = 1
for x in range(101):
    if x % 3 == 0:
        sum2 += x
print(sum2)

num2 = 0
num3 = 0
while  num3 <= 100:
    if num3 % 3 ==0 :
        num2 += num3
    num3 += 1
print(num2)

3. 计算1-100之间不不能被7整除的数的和

sum = 0
x = 1
for x in range(101):
    if x % 7 != 0:
        sum += x
print(sum)

num2 = 0
num3 = 0
while  num3 <= 100:
    if num3 % 7 !=0 :
        num2 += num3
    num3 += 1
print(num2)

print('我是一条优雅的分割线')