人生苦短，我要快乐学Python！之 4.练习题

1、使用while循环输入 1 2 3 4 5 6     8 9 10

n = 1
while n < 11:
    if n == 7:
        pass
    else:
        print(n)
    n = n + 1
print('----end----')

2、求1-100的所有数的和

n = 1
s = 0
while n < 101:
    s = s + n
    n = n + 1

print(s)

3、输出 1-100 内的所有奇数

n = 1
while n < 101:
    temp = n % 2
    if temp == 0:
        pass
    else:
        print(n)
    n = n + 1

print('----end----')

4、输出 1-100 内的所有偶数

n = 1
while n < 101:
    temp = n % 2
    if temp == 0:
        print(n)
    else:
        pass
    n = n + 1

print('----end----')

5、用户登陆（三次机会重试）

count = 0
while count < 3:
    user = input('>>>')
    pwd = input('>>>')
    if user == 'alex' and pwd == '123':
        print('欢迎登陆')
        print('..........')
        break
    else:
        print('用户名或者密码错误')
    count = count + 1

6、求1-2+3-4+5 ... 99的所有数的和

n = 1
s = 0 # s是之前所有数的总和
while n < 100:
    temp = n % 2
    if temp == 0:
        s = s - n    
    else:
        s = s + n            
    n = n + 1
print(s)