一个很有趣的程序员等级考试题----求循环小数
前几天公司公司一直有程序员面试，经理出了这样一道面试题：求两个数相除的商，并计算出小数点后的循环部分。例如1/3 商为0.333333333... ，则表示为0.(3)
当时，我也没见过这样的题，呵呵！实在惭愧！于是，下班回到家用asp.net简单实现以下：
aspx页：
代码
1
<%
@ Page Language
=
"
C#
"
AutoEventWireup
=
"
true
"
CodeFile
=
"
Default5.aspx.cs
"
Inherits
=
"
Default5
"
%>
2
3
<!
DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
>
4
5
<
html
xmlns
="http://www.w3.org/1999/xhtml"
>
6
<
head
runat
="server"
>
7
<
title
></
title
>
8
</
head
>
9
<
body
>
10
<
form
id
="form1"
runat
="server"
>
11
<
div
>
12
<
p
>
13
除数：
<
asp:TextBox
ID
="txtDivisor"
runat
="server"
onkeyup
="if(event.keyCode!=37&&event.keyCode!=39)value=value.replace(/\D/g,'');"
></
asp:TextBox
>
14
</
p
>
15
<
p
>
16
被除数：
<
asp:TextBox
ID
="txtDividend"
runat
="server"
onkeyup
="if(event.keyCode!=37&&event.keyCode!=39)value=value.replace(/\D/g,'');"
></
asp:TextBox
>
17
</
p
>
18
<
p
>
19
小数个数：
<
asp:TextBox
ID
="txtCount"
runat
="server"
onkeyup
="if(event.keyCode!=37&&event.keyCode!=39)value=value.replace(/\D/g,'');"
></
asp:TextBox
>
20
</
p
>
21
<
asp:Button
ID
="btnResults"
runat
="server"
Text
="结果"
22
onclick
="btnResults_Click"
/>
23
<
p
>
24
<
asp:Label
ID
="lbResults"
runat
="server"
Text
=""
></
asp:Label
>
25
</
p
>
26
</
div
>
27
</
form
>
28
</
body
>
29
</
html
>
aspx.cs页：
代码
1
using
System;
2
using
System.Collections.Generic;
3
using
System.Linq;
4
using
System.Web;
5
using
System.Web.UI;
6
using
System.Web.UI.WebControls;
7
8
public
partial
class
Default5 : System.Web.UI.Page
9
{
10
protected
void
Page_Load(
object
sender, EventArgs e)
11
{
12
if
(IsPostBack)
13
{
14
txtDivisor.Text
=
txtDivisor.Text;
15
txtDividend.Text
=
txtDividend.Text;
16
txtCount.Text
=
txtCount.Text;
17
}
18
}
19
protected
void
btnResults_Click(
object
sender, EventArgs e)
20
{
21
if
(txtDivisor.Text.Trim().Length
<
1
)
22
{
23
return
;
24
}
25
if
(txtDividend.Text.Trim().Length
<
1
)
26
{
27
return
;
28
}
29
if
(txtCount.Text.Trim().Length
<
1
)
30
{
31
return
;
32
}
33
34
int
_divisor
=
Convert.ToInt32(txtDivisor.Text);
35
int
_dividend
=
Convert.ToInt32(txtDividend.Text);
36
int
_count
=
Convert.ToInt32(txtCount.Text);
37
if
(_dividend
==
0
)
38
{
39
return
;
40
}
41
lbResults.Text
=
DivResult(_divisor, _dividend, _count);
42
43
}
44
//
运算主体
45
protected
string
DivResult(
int
divisor,
int
dividend,
int
count)
46
{
47
string
_divresult
=
""
;
48
int
tempdivisor
=
0
;
49
for
(
int
i
=
0
; i
<=
count; i
++
)
50
{
51
if
(i
==
0
)
52
{
53
_divresult
=
(divisor
/
dividend).ToString()
+
"
.
"
;
54
tempdivisor
=
divisor
%
dividend;
55
}
56
else
57
{
58
int
_tempdivisor
=
MaxMin(tempdivisor, dividend);
59
if
(_tempdivisor
!=
0
)
60
{
61
_divresult
=
_divresult
+
ReturnZero(_tempdivisor, tempdivisor)
+
(_tempdivisor
/
dividend).ToString();
62
tempdivisor
=
_tempdivisor
%
dividend;
63
}
64
else
65
{
66
_divresult
=
_divresult
+
'
0
'
;
67
}
68
}
69
}
70
string
[] temp
=
_divresult.Split(
'
.
'
);
71
string
temp1;
72
temp1
=
temp[
1
]
=
temp[
1
].Length
<
count
?
temp[
1
] : temp[
1
].Substring(
0
, count);
73
string
_repeatstr
=
CheckRepeat(temp[
1
]);
74
if
(_repeatstr.Length
>
0
)
75
{
76
temp[
1
]
=
temp[
1
].Remove(temp[
1
].IndexOf(_repeatstr))
+
"
(
"
+
_repeatstr
+
"
)
"
;
77
}
78
79
return
temp[
0
]
+
"
.
"
+
temp[
1
]
+
"
<br/>
"
+
temp[
0
]
+
"
.
"
+
temp1;
80
}
81
//
判断返回的零
82
private
string
ReturnZero(
int
_tempdivisor,
int
tempdivisor)
83
{
84
int
n
=
(
int
)Math.Log10(_tempdivisor
/
tempdivisor);
85
string
ret
=
""
;
86
for
(
int
i
=
1
; i
<
n; i
++
)
87
{
88
ret
+=
'
0
'
;
89
}
90
return
ret;
91
}
92
//
判断除数与被除数的大小
93
private
int
MaxMin(
int
divisor,
int
dividend)
94
{
95
if
(divisor
>
dividend
&&
divisor
!=
0
)
96
{
97
return
divisor;
98
}
99
else
if
(divisor
==
0
)
100
{
101
return
divisor;
102
}
103
else
104
{
105
return
MaxMin(divisor
*
10
, dividend);
106
}
107
}
108
//
判断小数点后的循环部分
109
private
string
CheckRepeat(
string
oldstr)
110
{
111
int
[] olditems
=
new
int
[oldstr.Length];
112
for
(
int
i
=
0
; i
<
oldstr.Length; i
++
)
113
{
114
olditems[i]
=
Convert.ToInt32(oldstr.Substring(i,
1
));
115
}
116
117
int
n
=
1
;
//
每次比较的次数
118
int
equalcount
=
0
;
//
每次比较相等的次数
119
for
(
int
i
=
olditems.Length
-
1
; i
>
olditems.Length
/
2
; i
--
)
120
{
121
equalcount
=
0
;
122
for
(
int
j
=
0
; j
<
n; j
++
)
123
{
124
if
(olditems[olditems.Length
-
1
-
j]
!=
olditems[olditems.Length
-
1
-
j
-
n])
125
{
126
break
;
127
}
128
equalcount
++
;
129
}
130
if
(n
==
equalcount)
131
{
132
break
;
133
}
134
n
++
;
135
}
136
string
ret
=
""
;
137
for
(
int
i
=
equalcount
-
1
; i
>=
0
; i
--
)
138
{
139
ret
+=
olditems[olditems.Length
-
1
-
i].ToString();
140
}
141
return
ret;
142
}
143
}
144
我只是简单的实现了一下！没有专门测试！如果有bug，请园友发消息告诉我啊！！ 呵呵..