std::numpunct::thousands_sep, std::numpunct::do_thousands_sep

From cppreference.com

Defined in header `<locale>`

public: char_type thousands_sep() const;	(1)

protected: char_type virtual do_thousands_sep() const;	(2)

1) public member function, calls the member function do_thousands_sep of the most derived class.

2) returns the character to be used as the separator between digit groups when parsing or formatting integers and integral parts of floating-point values.

[edit] Return value

The object of type char_type to use as the thousands separator. The standard specializations of std::numpunct return ’,’ and L’,’.

[edit] Example

run this code

#include <iostream>
#include <locale>
 
struct space_out : std::numpunct<char> {
    char do_thousands_sep()   const { return ' '; }  // separate with spaces
    std::string do_grouping() const { return "\1"; } // groups of 1 digit
};
 
int main()
{
    std::cout << "default locale: " << 12345678 << '\n';
    std::cout.imbue(std::locale(std::cout.getloc(), new space_out));
    std::cout << "locale with modified numpunct: " << 12345678 << '\n';
}

Output:

default locale: 12345678
locale with modified numpunct: 1 2 3 4 5 6 7 8

[edit] See also


do_grouping [virtual]	provides the numbers of digits between each pair of thousands separators (virtual protected member function)

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)