python 核心编程课后练习(chapter 5)

5-2

 #5-2
 def mul(x, y):
   return x * y

 print mul(4,5)  

5-3

 #5-3
 def value_score(num):
   if 90<=num<=100:
     return 'A'
   elif 80<=num<=89:
     return 'B'
   elif 70<=num<=79:
     return 'C'
   elif 60<=num<=69:
     return 'D'
   elif 0<=num<=59:
     return 'F'
   else:
     print "invalid value"         

 print value_score(90)
 print value_score(1000)
 print value_score(0) 

5-4

 #5-4
 def Leap_year(year):
   if year%4 == 0 and year%100 == 0 :
     return True
   elif year%4 == 0 and year%100 != 0 :
     return True
   else:
     return False

 if Leap_year(2004):
   print "leap year"
 else:
   print "common year" 

5-5

 #5-5
 import random

 def least_cents(cts):
   left = 0
   sum = 0
 #get the coins of 25cents
   sum = cts/25
   left = cts%25
 #get the coins of 10cents
   sum += left/10
   left = left%10
 #get the coins of 5cents
   sum += left/5
   left = left%5
 #get the coins of 1cents
   sum += left

   return sum

 cents = random.randint(1, 100)

 print "%d cents will have at least: %d coins" % (cents, least_cents(cents))

5-6

 #5-6

 def add(x, y):
   return x + y

 def sub(x, y):
   return x - y

 def mul(x, y):
   return x * y

 def div(x, y):
   return float(x)/float(y)      

 def mod(x, y):
   return x % y

 def pow(x, y):
   return x ** y

 def cal(str):
   a = []
   if(len(str.split('**')) == 2):
     a = str.split('**')
     return pow(int(a[0]), int(a[1]))
   elif (len(str.split('*')) == 2):
     a = str.split('*')
     return mul(int(a[0]), int(a[1]))
   elif (len(str.split('%')) == 2):
     a = str.split('%')
     return mod(int(a[0]), int(a[1]))
   elif (len(str.split('+')) == 2):
     a = str.split('+')
     return add(int(a[0]), int(a[1]))
   elif (len(str.split('-')) == 2):
     a = str.split('-')
     return sub(int(a[0]), int(a[1]))
   else:
     print "Not support"  

 print "enter the formula:"
 formula_str = raw_input()
 print cal(formula_str)    

5-7

 #5-7
 def tax(num):
   return num * 0.03

 turnover = raw_input("enter the turnover:")
 print"the tax you need to turn over to the state: %f" %(tax(int(turnover)))

5-8

 #5-8
 import math
 def suqare_area(len):
   return float(len) * float(len)

 def suqare_volume(len):
   return float(len) ** 3

 def circle_area(r):
   return math.pi * float(r) * float(r)

 def spere_volum(r):
   return 4 * math.pi * float(r) * float(r) * float(r)/ 3.0

 len = raw_input("enter the len:")

 print "the area of suqare is: %f" % suqare_area(len)
 print "the volume of square is: %f" % suqare_volume(len)       

 r = raw_input("enter the r:")
 print "the area of the circle is: %f" % circle_area(r)
 print "the volume of spere is: %f" % spere_volum(r)

5-10

 #5-10
 def fah_to_centi(c):
   return (c - 32)*(5/float(9))

 c = raw_input("enter the fahrenheit:")

 print "the centi degrees is: %f" % fah_to_centi(float(c))

5-11

 #5-11
 def odd_num(num):
   return num %2 == 1

 def aliquant(n1, n2):
   return n1 % n2 == 0

 for e in range(0, 20):
   if not odd_num(e):
     print "even number:%d" % e

 for e in range(0, 20):
   if odd_num(e):
     print "odd number: %d" % e  

 n1 = raw_input("enter the first number:")
 n2 = raw_input("enter the second number:")
 if aliquant(int(n1), int(n2)):
   print"aliquant"
 else:
   print"not aliquant"  

5-12

 #5-12
 import sys

 print sys.maxint
 print -sys.maxint - 1

 print sys.float_info.max
 print sys.float_info.min

5-13

 #5-13

 def hm_to_m(str):
   a = str.split(':')
   return int(a[0])* 60 + int(a[1])

 hm = raw_input("enter the time:")

 print "the currents mins is: %d" % hm_to_m(hm)  

5-14

 #5-14
 def year_rate():
   return (1+0.0385)** 365 - 1.0

 print year_rate()

5-15

 #5-15
 def GCD(m,n):
   if m%n == 0:
     return n
   else:
     return GCD(n, m%n) 

 def LCM(m, n):
   return m*n/GCD(m, n)

 m = int(raw_input("enter m:"))
 n = int(raw_input("enter n:"))

 print"the GCD of %d, %d is: %d" % (m, n, GCD(m, n))
 print"the LCM of %d, %d is: %d" % (m, n, LCM(m, n))  

5-17

 #5-17
 import random

 N = random.randint(2, 100)
 a = []

 def show_all(a):
   for i in range(len(a)):
     print a[i]

 for i in range(0, N-1):
   tmp = random.randint(2, 2**31)
   a.append(tmp)
 print "Original:"
 show_all(a)

 for i in range(0, N-1):
   for j in range(i, N-1):
     if a[i] > a[j]:
       a[i], a[j] = a[j], a[i]

 print"New arrary:"
 show_all(a)