除以 1000 ， 对余数进行处理
1 #include <iostream>
2 using namespace std;
3
4 char* reverse(char* s, int low, int high)
5 {
6 while (low < high)
7 {
8 s[low] ^= s[high];
9 s[high] ^= s[low];
10 s[low] ^= s[high];
11 ++low;
12 --high;
13 }
14 return s;
15 }
16
17 char* format_thousands_separator(char a[], unsigned long val)
18 {
19 char* ret = a;
20 char temp[4];
21 int t;
22 int n = 0;
23 while (val > 1000)
24 {
25 t = val % 1000;
26 if (t >= 100)
27 {
28 itoa(t, temp, 10);
29 reverse(temp, 0, 2);
30 //cout << temp << endl;
31 strcat(ret, temp);
32 //cout<< "test" << ret << endl;
33 }
34 else if (t >= 10)
35 {
36 itoa(t, temp, 10);
37 reverse(temp, 0, 1);
38 strcat(ret, temp);
39 strcat(ret, "0");
40 }
41 else
42 {
43 itoa(t, temp, 10);
44 strcat(ret, temp);
45 strcat(ret, "00");
46 }
47 strcat(ret, ",");
48 n += 4;
49 val /= 1000;
50 ret[n] = '\0';
51 cout << ret << endl;
52 }
53 if (val >= 100)
54 {
55 itoa(val, temp, 10);
56 reverse(temp, 0, 2);
57 strcat(ret, temp);
58 n += 3;
59 }
60 else if (val >= 10)
61 {
62 itoa(val, temp, 10);
63 reverse(temp, 0, 1);
64 strcat(ret, temp);
65 n += 2;
66 }
67 else
68 {
69 itoa(val, temp, 10);
70 strcat(ret, temp);
71 ++n;
72 }
73 reverse(ret, 0, n - 1);
74 ret[n] = '\0';
75 return ret;
76 };
77
78 int main()
79 {
80 unsigned long ul;
81 char sul[20] = {0};
82 while (cin >> ul)
83 {
84 cout << format_thousands_separator(sul, ul) << endl;
85 }
86 return 0;
87 }
先转换成一个 字符串 ，然后从右扫描，加逗号，然后反转
1 #include <iostream>
2 #include <sstream>
3 #include <string>
4 #include <algorithm>
5 using namespace std;
6
7 const string& format_thousands_separator(string& s, unsigned long val)
8 {
9 s.clear();
10 char t[20];
11 string temp(ltoa(val, t, 10));
12
13 int n = 0;
14 for (string::const_reverse_iterator cit = temp.rbegin(); cit != temp.rend(); ++cit)
15 {
16 ++n;
17 s += *cit;
18 if (n == 3)
19 {
20 s += ',';
21 n = 0;
22 }
23 }
24 reverse(s.begin(), s.end());
25 return s;
26 }
27
28 int main()
29 {
30 unsigned long ul;
31 string sul;
32 while (cin >> ul)
33 {
34 cout << format_thousands_separator(sul, ul) << endl;
35 }
36 return 0;
37 }
http://www.cppblog.com/qinqing1984/archive/2011/06/24/149366.html
posted on 2011-06-24 16:46
unixfy 阅读(455)
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