1 #include <iostream>
 2 #include <string>
 3 #include <sstream>
 4 #include <regex>
 5 
 6 std::string ToThousandsNum(int num)
 7 {
 8     std::stringstream ss;
 9     ss << num;
10 
11     std::string str = ss.str();
12     std::regex pattern("^(-?\\d+)(\\d{3})
 
");
13 
14     while (true)
15     {
16         str = std::regex_replace(str, pattern, "$1,$2");
17         if (!std::regex_search(str, pattern))
18             break;
19     }
20 
21     return str;
22 }

c++ 正則實現 千分位分割