第5章

Posted 2020-06-17

5-1：

标准整型通常的取值范围是：-2147483648~2147483647，长整型能表达的数值仅与机器支持的（虚拟）内存大小有关，即能轻松表达很大的整型。在一个整型值后面加个L即表示长整型。

5-2：

#!/usr/bin/env python
def myProduct(a, b):　　#(a)
    return a * b

x = 5　　#(b)
y = 6
ans = myProduct(x, y)
print ans

5-3:

#!/usr/bin/env python
test = int(raw_input(‘Enter test score: ‘))
if 90 <= test <= 100:
    print ‘A‘
elif 80 <= test <= 89:
    print ‘B‘
elif 70 <= test <= 79:
    print ‘C‘
elif 60 <= test <= 69:
    print ‘D‘
elif test < 60:
    print ‘F‘

5-4:

#!/usr/bin/env python
year = int(raw_input(‘-> ‘))
if (year%4 == 0 and year%100 != 0) or (year%400 == 0):
    print ‘leap year‘
else:
    print ‘not leap year‘

5-5:

#!/usr/bin/env python
money = 100 * float(raw_input(‘-> ‘))
quarter = money / 25
money = money % 25
dimes = money / 10
money = money % 10
nickel = money / 5
money = money % 5
penny = money / 1
print ‘%d quarter, %d dimes, %d nickel, %d penny‘ % (quarter, dimes, nickel, penny)

5-6:

#!/usr/bin/env python
exp = raw_input().split()
op = exp[1]
if op == ‘+‘:
    print float(exp[0]) + float(exp[2])
elif op == ‘-‘:
    print float(exp[0]) - float(exp[2])
elif op == ‘*‘:
    print float(exp[0]) * float(exp[2])
elif op == ‘/‘:
    print float(exp[0]) / float(exp[2])
elif op == ‘%‘:
    print float(exp[0]) % float(exp[2])
elif op == ‘**‘:
    print float(exp[0]) ** float(exp[2])

5-7:

#!/usr/bin/env python
from decimal import Decimal
billing = Decimal(raw_input())
tax = billing * Decimal(‘0.06‘)
print tax

5-8：

#!/usr/bin/env python
import math

def sqcube():
    s = float(raw_input(‘enter length of one side: ‘))
    print ‘the area is:‘, s ** 2., ‘(units squared)‘
    print ‘the volumn is:‘, s ** 3., ‘(cubic units)‘

def cirsph():
    r = float(raw_input(‘enter length of radius: ‘))
    print ‘the area is:‘, math.pi * (r ** 2.), ‘(units squared)‘
    print ‘the volumn is:‘, (4. / 3.) * math.pi * (r ** 3.), ‘(cubic units)‘

sqcube()
cirsph()

5-9：

（a）：因为017为八进制表示，它所代表的十进制数为15，同理，八进制的032代表十进制的26

（b）：因为两个操作数分别为56L和78L，不是561和781，错将小写l误认为1

5-10：

#!/usr/bin/env python
from __future__ import division

def f2c(f):
    c = (f - 32) * (5 / 9)
    return c

5-11：

（a）：

#!/usr/bin/env python
from __future__ import division

def f2c(f):
    c = (f - 32) * (5 / 9)
    return c

print f2c(10)

（b）:

#!/usr/bin/env python
num = 0
while num <= 20:
    if num % 2 == 1:
        print num
    num += 1

（c）：

判断是否能被2整除，如果能，就是偶数，否则就是奇数。

（d）:

#!/usr/bin/env python
def f(a, b):
    if (a % b == 0) or (b % a == 0):
        return True
    return False

print ‘Enter two numbers‘
x = int(raw_input(‘->‘))
y = int(raw_input(‘->‘))
print f(x, y)

5-12：

import sys

print sys.maxint    #int最大值
print -sys.maxint-1    #int最小值
print sys.float_info.max    #float最大值
print sys.float_info.min    #float最小值

长整型能表达的数值仅仅与机器支持的（虚拟）内存大小有关。

通过type(num.real), type(num.imag)可知复数类型的实部和虚部都是浮点型，而前面已经得到了浮点型的范围。

 

5-13：

print ‘Enter a time such as 3:50‘
t = raw_input(‘->‘)
minute = int(t.split(‘:‘)[0]) * 60 + int(t.split(‘:‘)[1])
print minute

 5-14：

#!/usr/bin/env python
def f(rate):
    ans = (1 + rate) ** 365 - 1
    return ans

5-15:

def gcd(a, b):
    while True:
        if a % b == 0:
            return b
        else:
            a, b = b, a % b

def lcm(a, b):
    return a * b / gcd(a, b)

5-16:

#!/usr/bin/env python
ob = float(raw_input(‘Enter opening balance: ‘))
mp = float(raw_input(‘Enter monthly payment: ‘))
print ‘     \tAmount\tRemaining‘
print ‘Pymt#\t Paid \t Balance‘
print ‘-----\t------\t---------‘
count = 0
paid = 0
remain = ob
while remain >= 0:
    print ‘%d\t$%5.2f\t$%6.2f‘ % (count, paid, remain)
    if remain == 0:
        break
    count += 1
    if remain > mp:
        paid = mp
    else:
        paid = remain
    remain -= paid

5-17*:

#!/usr/bin/env python
import random
N = random.randint(2, 100)
count = 0
alist = []
while count < N:
    alist.append(random.randint(0, 2**31 - 1))
    count += 1
c = random.randint(2, N)
count = 0
blist = []
while count < c:
    ele = random.choice(alist)
    blist.append(ele)
    alist.remove(ele)
    count += 1
blist.sort()
print blist