1.程序结构图
2.实现源码
1 import re
2
3 def add_func(x,y):
4 return eval(x)+eval(y)
5
6 def subtract_func(x,y):
7 return eval(x)-eval(y)
8
9 def multiple_func(x,y):
10 return eval(x)*eval(y)
11
12 def division_func(x,y):
13 return eval(x)/eval(y)
14
15 def power_func(x,y):
16 return eval(x)**eval(y)
17
18 while True:
19 content = input("请输入你想要处理的计算式子: >>>")
20 est = re.search('[^0-9+\-*/().]', content)
21 if est:
22 print("you input invalid character")
23 receive = input("please input any character to continue or input q to quit >>>")
24 if receive == "q":
25 exit()
26 else:
27 continue
28 else:
29 break
30
31 print(eval(content))
32 bracket_switch = False
33 cal_switch = False
34 power_flag = False
35 func_list = [add_func, subtract_func, multiple_func, division_func, power_func]
36 cal_character_list = ["\+", "-", "\*", "/", "\*\*"]
37
38 while True:
39 matching_bracket = re.search("\([^()]+\)", content)
40 if matching_bracket:
41 matching_content = matching_bracket.group()
42 accept = matching_content[1:-1]
43 else:
44 accept = content
45 bracket_switch = True
46 while True:
47 if "**" in accept:
48 cal_matching = re.search("-?[\d.]+\*\*-?[\d.]+", accept)
49 elif "/" in accept:
50 cal_matching = re.search("-?[\d.]+/-?[\d.]+", accept)
51 elif "*" in accept:
52 cal_matching = re.search("-?[\d.]+\*-?[\d.]+", accept)
53 else:
54 cal_matching = re.search("-?[\d.]+[+\-]-?[\d.]+", accept)
55
56 if cal_matching:
57 result = cal_matching.group()
58 # print(result)
59 filter_one = re.search("\d.+\d", result).group()
60 filter_two = re.search("[+\-*/]{2,3}", filter_one)
61 if filter_two:
62 judge = filter_two.group()
63 if "**" in filter_one:
64 choice = 4
65 power_flag = True
66 cal_character = cal_character_list[choice]
67 elif "*" in judge:
68 choice = 2
69 cal_character = cal_character_list[choice]
70 elif "/" in judge:
71 choice = 3
72 cal_character = cal_character_list[choice]
73 else:
74 if "+" in filter_one:
75 choice = 0
76 cal_character = cal_character_list[choice]
77 elif "-" in filter_one:
78 choice = 1
79 cal_character = cal_character_list[choice]
80 elif "*" in filter_one:
81 choice = 2
82 cal_character = cal_character_list[choice]
83 elif "/" in filter_one:
84 choice = 3
85 cal_character = cal_character_list[choice]
86
87 if not power_flag:
88 count_result = func_list[choice](re.findall(".+%s" %cal_character, result)[0][:-1], re.findall("%s.+" %cal_character, filter_one)[0][1:])
89 # print(count_result)
90 if (choice == 2 or choice == 3) and result.count("-") == 2:
91 accept = re.sub("%s%s%s" % (re.findall(".+%s" %cal_character, result)[0][:-1], cal_character,re.findall("%s.+" %cal_character, result)[0][1:]), "+"+str(count_result), accept, 1)
92 else:
93 accept = re.sub("%s%s%s" % (re.findall(".+%s" %cal_character, result)[0][:-1], cal_character, re.findall("%s.+" %cal_character, filter_one)[0][1:]), str(count_result), accept, 1)
94 else:
95 count_result = func_list[choice](re.findall(".+%s" % cal_character, result)[0][:-2], re.findall("%s.+" % cal_character, result)[0][2:])
96 accept = re.sub("%s%s%s" % (re.findall(".+%s" % cal_character, result)[0][:-2], cal_character,re.findall("%s.+" % cal_character, result)[0][2:]), str(count_result), accept, 1)
97 power_flag = False
98
99 else:
100 print(content)
101 content = re.sub("\([^()]+\)", str(count_result), content, 1)
102
103 #去除括号后，解决+-；--的情况
104 double_character = re.search('[\-+]{2}', content)
105 if double_character:
106 if "+-" in content:
107 content = re.sub("[\-+]{2}", "-", content)
108 elif "--" in content:
109 content = re.sub("[\-+]{2}", "+", content)
110
111 if bracket_switch:
112 content = re.sub(".+", str(count_result), content)
113 cal_switch = True
114 break
115
116 if cal_switch:
117 break
118
119 print(content)
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