String类型的二进制数求和

 1 public static string er(string a, string b)
 2         {
 3             int l;
 4             if (a.Length>b.Length)
 5             {
 6                 l = a.Length;
 7             }
 8             else
 9             {
10                 l = b.Length;
11             }
12             char[] c1 = new char[l];
13             char[] c2 = new char[l];
14             char p='0';
15             char[] c3 = new char[l + 1];
16             for (int j = 0; j < l+1; j++)
17             {
18                 c3[j] = '0';
19             }
20             StringReader sra = new StringReader(a);
21             sra.Read(c1, 0, l);
22             StringReader srb = new StringReader(b);
23             srb.Read(c2, 0, l);
24             sra.Close();
25             srb.Close();
26             for (int i= l-1; i>=0; i--)
27             {
28                 if (c1[i]=='0'&&c2[i]=='0')
29                 {
30                     if (p=='1')
31                     {
32                         c3[i + 1] = '1';
33                         p = '0';
34                     }
35                     else
36                     {
37                         c3[i + 1] = '0';
38                     }
39                 }
40                 else if (!(c1[i] == '1' && c2[i] == '1'))
41                 {
42                     if (p == '1')
43                     {
44                         c3[i + 1] = '0';
45                     }
46                     else
47                     {
48                         c3[i + 1] = '1';
49                     }
50                 }
51                 else
52                 {
53                     if (p == '1')
54                     {
55                         c3[i + 1] = '1';
56                     }
57                     else
58                     {
59                         c3[i + 1] = '0';
60                         p = '1';
61                     }
62                 }
63             }
64             if (p=='1')
65             {
66                 c3[0] = '1';
67             }
68             StringBuilder c =new StringBuilder("");
69             StringWriter sw = new StringWriter(c);
70             sw.Write(c3, 0, l+1);
71             sw.Close();
72             return c.ToString();
73         }

1 string x = "1010101";
2 string y = "1101010";
3 Console.WriteLine(x+"+"+y+"=");
4 string z = "";
5 z = er(x, y);
6 Console.WriteLine(z.ToString());
7 Console.ReadLine();