python学习第1天
练习题
练习1
使用while循坏输出1 2 3 4 5 6 8 9 10
方法1
count = 1
while count < 11:
if count != 7:
print(count)
count += 1
方法2
count = 0
while count < 10:
count += 1
if count == 7:
continue
print(count)
方法3
count = 1
while count < 11:
if count == 7:
pass
else:
print(count)
count = count +1
print()
练习2
求1+2+3+.....+100的和
方法1
sum = 0
count = 1
while count < 101:
sum = sum + count
count += 1
print(sum)
方法2
count = 1
s = 0
while count < 101:
s = s + count
count = count + 1
print(s)
练习3
求1--100的所有奇数
方法1
count = 1
s = 0
while count < 101:
s = s + count
count = count + 1
print(s)
方法2
count = 1
while count < 101:
temp = count % 2
if temp == 0:
pass
else:
print(count)
count = count + 1
print()
练习4
求1--100的所有偶数
方法1
count = 1
while count < 101:
if count % 2 == 0:
print(count)
count += 1
方法2
count = 1
while count < 101:
temp = count % 2
if temp == 0:
print (count)
else:
pass
count = count + 1
print ()
练习5
求1-2+3-4+5....+99的和
方法1
sum1 = 0
sum2 = 0
count = 1
while count < 100:
if count % 2 != 0:
sum1 = sum1 + count
else:
sum2 = sum2 - count
count += 1
print(sum1 + sum2)
方法2
num = 1
num2 = 2
num3 = num - num2
while True:
num += 2
num2 += 2
num3 =num + num3
if num == 99:
break
num3 = num3 - num2
print(num3)
方法3
sum = 1
s = 0
while True:
s = s +sum
if sum == 99:
break
sum += 2
sum1 = 0
s1 = 0
while True:
s1 = s1 + sum1
if sum1 == 98:
break
sum1 += 2
print(s - s1)
方法4
sum = 0
count = 1
while start < 100:
temp = start % 2
if temp == 1:
sum =sum + count
else:
sum =sum - count
count += 1
print(sum)
方法5
sum = 1
s = 0
while sum < 100:
s = s + sum*(-1)**(sum + 1)
sum += 1
print(s)
方法6
print(49*(1 - 2)+99)
练习6
用户登录（三次机会重试）
基本的功能：
user ='script_child'
pwd ='123456'
count = 1
while True:
if count == 4:
print('Too many times!!')
break
username = input('Please enter your user name:').strip()
password = input('Please enter your user password:')
if username == user and password == pwd:
print('Login successfully!!')
else:
print('Login failed!!')
count += 1
去除bug，添加一些功能：
添加限制：当用户连续输入错误次数超过三次，就锁定这个用户
user = 'script_child'
pwd = '123456'
count = 1
while True:
if count == 4:
print('Too many times!')
break
username = input('Please enter your username:').strip()
password = input('Please enter your password:')
if not username:
print('The username you entered is blank, please re-enter')
continue
elif not password:
print('The password you entered is blank, please re-enter')
continue
if username == user and password == pwd:
print('Login successfully!!')
break
else:
print('The username or password you entered is incorrect,Please try again!')
print('You still have %s chances'%(3-count))
count += 1
再添加一些功能：
要求：1、用户输入账号或密码为空时，让用户反复输入并提示让其输入用户名和密码
2、每登陆一次失败后就告之用户还有几次机会
3、用户登陆成功后让用户输入命令，用户输入什么命令就打印这个命令，如果用户输入的命令为“q 则退出整个程序
user = 'script_child'
pwd = '123'
tag = True
count = 1
while tag:
if count == 4:
print('Too many times!')
break
username = input('Please enter your username:').strip()
password = input('Please enter your password:')
if not username:
print('The username you entered is blank,please re-enter')
continue
elif not password:
print('The password you entered is blank, please re-enter')
continue
if username == user and password == pwd:
print('Login successfully！！')
while tag:
user_cmd = input('Please enter your command:').strip()
if user_cmd == 'q':
tag = False
break
print('Your command is %s' % user_cmd)
else:
print('The username or password you entered is incorrect,Please try again!')
print('You still have %s chances'%(3-count))
count += 1
