零基础学习Python 作业 第4章

———-CH04 homework———-

0.请问以下代码会打印多少次“我爱鱼C！”

Answer: 无限次，因为’C’ = 67 == truth，满足while的循环条件

1.请问以下代码会打印多少次“我爱鱼C！”

1.  i = 10
2.  while i:
3.  print('我爱鱼C!')
4.  i = i - 1

Answer: 10次

1. 请写出与 10 < cost < 50 等价的表达式

Answer： 10 < cost and cost < 50

1. Python3 中，一行可以书写多个语句吗？

Answer: 用分号隔开
e.g. >>> print(‘I love you’);print(5)

1. Python3 中，一个语句可以分成多行书写吗？

Answer: 反斜杠’\’ 或者 括号’()’

e.g.
>>> 5>4 and \
    6>3
>>> (3>2 and
 2>1)

5.请问Python的 and 操作符 和 C语言的 && 操作符 有何不同？【该题针对有C或C++基础的朋友】
Answer:
C && test

#include 

int main()
{
    int a = 5;
    int b = 3;
    int c = 1;
    printf("The result of ( a > b && b > c) is %d\n", (a > b) && (b > c));
    return 0;
}

gcc test
The result of ( a > b && b > c) is 1
请按任意键继续. . .

结论：C语言中 && 操作符是逻辑运算符，备注：C语言中 & 是位操作符

Python Test
>>> 1 and 0
0
>>> 0 and 0
0
>>> 1 and 1
1

and 是逻辑预算符，同时也是bool运算符，>>> (3>2 and 2>1) 返回 True

6 听说过“短路逻辑（short-circuit logic）”吗？

Answer: 逻辑操作符有个有趣的特性：在不需要求值的时候不进行操作。这么说可能比较“高深”, ‘不做无用功’
e.g.表达式 x and y，需要 x 和 y 两个变量同时为真(True)的时候，结果才为真。
因此，如果当 x 变量得知是假(False)的时候，表达式就会立刻返回 False，而不用去管 y 变量的值。
这种行为被称为短路逻辑（short-circuit logic）或者惰性求值（lazy evaluation）

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Practice

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1.

The First method
import random
secret = random.randint(1, 100)
print('----------Talk to me wow----------')
temp  = input('Please enter a number(1~100):')
guess = int(temp)
count = 0
while guess != secret:
    if count > 6:
        print('sorry! You guess 6 times')
        print('Thanks\n')
        break

    if guess > secret:
        print('You guess bigger')
        count = count + 1
    else:
        print('You guess smaller')
        count = count + 1
    print('You have 7 times guess and You have', 7 - count, 'times')

    temp = input('Please enter a number(1~100) again :')
    guess = int(temp)

    if guess == secret:
        print('Wonderful! You guess right')
    else:
        if guess > secret:
            print('You guess bigger')
            count = count + 1
        else:
            print('You guess smaller')
            count = count + 1
        print('You have 7 times guess and You have', 7 - count, 'times')
        temp = input('Please enter a number(1~100) again :')
        guess = int(temp)

print('Congratulation!')
print('Game Over')

The second method:

import random
secret = random.randint(1, 100)
print('----------Talk to me wow----------')
guess = 0
count = 7

while guess != secret and count > 0:
    print('All 7 times, and You still have ', count, ' chances')
    temp  = input('Please enter a number(1~100):')
    guess = int(temp)
    count = count - 1
    if guess == secret:
        print('Wonderful! Congration!')
    else:
        if guess > secret:
            print('You guess bigger!')
        else:
            print('You guess smaller!')
        if count > 0:
            print('You can continue!')
        else:
            print('No chances! Bye')
print('Game Over')

TEST resu----------Talk to me wow----------
All 7 times, and You still have  7  chances
Please enter a number(1~100):50
You guess smaller!
You can continue!
All 7 times, and You still have  6  chances
Please enter a number(1~100):75
You guess smaller!
You can continue!
All 7 times, and You still have  5  chances
Please enter a number(1~100):88
You guess bigger!
You can continue!
All 7 times, and You still have  4  chances
Please enter a number(1~100):82
You guess bigger!
You can continue!
All 7 times, and You still have  3  chances
Please enter a number(1~100):78
You guess smaller!
You can continue!
All 7 times, and You still have  2  chances
Please enter a number(1~100):80
You guess smaller!
You can continue!
All 7 times, and You still have  1  chances
Please enter a number(1~100):81
Wonderful! Congration!
Game Over

2.

temp = input('Please enter a number(1~10): ')
num = int(temp)
i = 1

while num:
    print(i)
    i = i + 1
    number = number -1

3.

temp = input('please enter a number(1~10): ')
num = int(temp)
i = num
if num > 10 or num < 1:
    print('number 1~10 !!!')
else:
    while i:
        print('*' * i)
        i = i - 1