1 # 整数部分十进制转二进制

  2

  3 num = int(raw_input(">>>"))

  4

  5 if num < 0:

  6     isNeg = True

  7     num = abs(num)

  8 else:

  9     isNeg = False

 10 result = ''

 11 if num == 0:

 12     result = ''

 13 while num > 0:

 14     result = str(num%2) + result

 15     num = num/2

 16 if isNeg:

 17     result = '-' + result

 18 # 小数部分十进制转二进制

 19

 20 x = float(raw_input('Enter a decimal number between 0 and 1: '))

 21

 22 p = 0

 23 while ((2**p)*x)%1 != 0:

 24     print('Remainder = ' + str((2**p)*x - int((2**p)*x)))

 25     p += 1

 26

 27 num = int(x*(2**p))

 28

 29 result = ''

 30 if num == 0:

 31     result = ''

 32 while num > 0:

 33     result = str(num%2) + result

 34     num = num/2

 35

 36 for i in range(p - len(result)):

 37     result = '' + result

 38

 39 result = result[0:-p] + '.' + result[-p:]

 40 print('The binary representation of the decimal ' + str(x) + ' is ' + str(result))

 # 穷举法猜测检验平方根

 x = 25

 epsilon = 0.01

 step = epsilon**2

 numGuesses = 0

 ans = 0.0

 while (abs(ans**2 - x)) >= epsilon and ans <= x:

     ans += step

     numGuesses += 1

 print('numGuesses = ' + str(numGuesses))

 if abs(ans**2-x) >= epsilon:

     print('Failed on square root of ' + str(x))

 else:

     print(str(ans) + ' is close to the square root of ' + str(x))

 # 二分法猜测检验平方根

 # bisection search for square root

 x = 12345

 epsilon = 0.01

 numGuesses = 0

 low = 0.0

 high = x

 ans = (high + low)/2.0

 while abs(ans**2 - x) >= epsilon:

     print('low = ' + str(low) + ' high = ' + str(high) + ' ans = ' + str(ans))

     numGuesses += 1

     if ans**2 < x:

         low = ans

     else:

         high = ans

     ans = (high + low)/2.0

 print('numGuesses = ' + str(numGuesses))

 print(str(ans) + ' is close to square root of ' + str(x))

 # Lecture 3.7, slide 3

 # 牛顿-罗斐逊 算法搜寻平方根（g-(g**2-k)/2g）

 epsilon = 0.01

 y = 24.0

 guess = y/2.0

 while abs(guess*guess - y) >= epsilon:

     guess = guess - (((guess**2) - y)/(2*guess))

     print(guess)

 print('Square root of ' + str(y) + ' is about ' + str(guess))

 #第一个python程序

 import pickle as p

 linkmanfile = 'linkman.data'

 #the name of the file where we will store the object

 linkman = {           'zhangyunpeng' :   '',

                             'xuleisen'            :   '',

                             'yinrui'                :   '',

                             'yancangkuo'     :   '',

                             'lijizhou'              :   '',

                             'liuyulong'           :   ''

 }

 #set up linkman data base

 print '%d lineman:' % len(linkman)

 for name, qq in linkman.items():

 print '%s : %s' % (name, qq)

 #list original listing

 print'(1-search 2-delete 3-add 0-revise)'

 #prompting of operation

 k = int(raw_input('please input:'))

 if k == 1:

 s = raw_input('Search the linkman name:')

 print '%s' % linkman[s]

 elif k == 2:

 d = raw_input('delete the linkman name:')

 del linkman[d]

 elif k == 3:

 a = raw_input('add the linkman name:')

 A = raw_input('add the linkman number:')

 linkman[a] = A

 elif k == 0:

 r = raw_input('which revise:')

 linkman[r] = raw_input('revised number:')

 #code of process

 for name, qq in linkman.items():

 print '%s : %s' % (name, qq)

 #print new listing

 f = file(linkmanfile, 'w')

 p.dump(linkman, f)

 #put data into a file for using next