Python 学习第一天（相关练习题）

1.使用while循环输出 1 2 3 4 5 6   8 9 10

1 count = 0
2 while count < 10:
3     count += 1
4     if count == 7:
5         continue
6     print(count)

2.求1-100的所有数的和

1 count = 1
2 sum = 0
3 while count <= 100:
4     sum += count
5     count += 1
6 print(sum)

3.输出1-100内的所有奇数

1 count = 0
2 odd = 0
3 while count < 50:
4     odd = count * 2 + 1
5     count += 1
6     print(odd)

4.输出1-100内的所有偶数

1 count = 0
2 even = 0
3 while count < 50:
4     count += 1
5     even = 2 * count
6     print(even)

5.求1-2+3-4+5-...-98+99的结果

方案一：

 1 count = 0
 2 change = 0
 3 sum = 0
 4 while count < 99:
 5     count += 1
 6     if count % 2 == 0:
 7         change = -1 * count
 8     else:
 9         change = count
10     sum += change
11 print(sum)

方案二：

1 power = 1
2 count = 0
3 sum = 0
4 while count < 99:
5     count += 1
6     power += 1
7     sum = sum + count*((-1)**power)
8 print(sum)
#鸣谢 Conan_1996 提供方法

6.用户登录（三次机会重试）

 1 user_name = 'admin'
 2 password = 'admin'
 3 chance = 0
 4 while chance < 3:
 5     chance += 1
 6     name = input("请输入用户名：")
 7     pw = input("请输入密码：")
 8     if name == user_name :
 9         if pw == password :
10             print("登录成功！")
11             break
12         else:print("用户名或密码输入错误，请重新输入！")
13     else: print("用户名或密码输入错误，请重新输入！")
14 if chance == 3:
15     print("今天的登录次数用完了，请明天再来")