Learn Python The first day (related exercises)

1. The while loop output 1234568910

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

2. All numbers 1-100 and seek

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

3. The outputs of all the odd-numbered 1-100

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

4. Output all even within 1-100

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

The result of evaluating 1-2 + 3-4 + 98 + 99 5 -...-

Option One:

 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)

Option II:

. 1 Power =. 1
 2 COUNT = 0
 . 3 SUM = 0
 . 4  the while COUNT <99 :
 . 5      COUNT + =. 1
 . 6      Power = +. 1
 . 7      SUM = SUM + COUNT * ((-. 1) ** Power)
 . 8  Print (SUM) 
# Acknowledgments Conan_1996 provides methods

6. User login (three chances to retry)

. 1 USER_NAME = ' ADMIN ' 
2 password = ' ADMIN ' 
. 3 Chance = 0
 . 4  the while Chance <. 3 :
 . 5      Chance + =. 1
 . 6      name = INPUT ( " Please enter your name: " )
 . 7      PW = INPUT ( " Enter Password: " )
 8      IF name == user_name:
 9          IF pw == password:
 10              Print ( " Login successful! " )
 11              BREAK
12          the else : Print ( " user name or password is entered incorrectly, please re-enter! " )
 13      the else : Print ( " user name or password is entered incorrectly, please re-enter! " )
 14  IF Chance == 3 :
 15      Print ( " today logins run out, please come back tomorrow " )