Fortran十进制和千位分隔符 [英] Fortran decimal and thousand separator

问题描述

是否可以更改逗号的句点小数点分隔符?

此外，如何使输出数字具有千位分隔符?这可能是逗号，句点，空格...

解决方案

您可以编写一个C ++函数，该函数将为您在当前语言环境中转换字符串中的数字.

  #include< string>#include< iomanip>#include< sstream>class SpaceSeparator:public std :: numpunct< char>{上市:SpaceSeparator(std :: size_t refs):std :: numpunct< char>(refs){}受保护的:char do_thousands_sep()const {return'';}char do_decimal_point()const {return'，';}std :: string do_grouping()const {返回"\ 03";}};extern"C" {void convert(char * str，double f，int len){std :: string s;std :: stringstream输出;SpaceSeparator facet(1);//1-完成后不要删除std :: locale prev = out.imbue(std :: locale(std :: locale()，&facet));出<<std :: setprecision(15)<<F;s = out.str();std :: copy(s.begin()，s.end()，str);我为(i = s.size(); i< len; i ++){str [i] ='';}}} 

从Fortran拨打电话:

 使用iso_c_binding界面子例程convert(str，f，l)bind(C，name ="convert")进口字符(c_char):: str(*)实(c_double)，值:: f整数(c_int)，值:: l结束子程序终端接口字符(len = 100，kind = c_char):: ch调用convert(ch，123456.123_c_double，len(ch，kind = c_int))打印*，ch结尾 

在我的机器上，它会打印 123 456,123 :

 >gfortran locale.cc locale.f90 -lstdc ++>./a.out123 456,123 

免责声明:我不是C ++程序员，他的解决方案可能很慢.也许Fortran中的蛮力方法更好.

我以这个答案为基础: https://stackoverflow.com/a/2648663/721644

Is there a way to change the period decimal separator for a comma?.

Also, how can I make the output numbers have a thousand separator?. This could be a comma, a period, a space ...

解决方案

You can write a C++ function which will convert the number in a string in you current locale for you.

#include <string>
#include <iomanip> 
#include <sstream>

class SpaceSeparator: public std::numpunct<char>
{
public:
    SpaceSeparator(std::size_t refs): std::numpunct<char>(refs) {}
protected:
    char do_thousands_sep() const { return ' '; }
    char do_decimal_point() const { return ','; }
    std::string do_grouping() const { return "\03"; }
};

extern "C" {

void convert(char* str, double f, int len) {
  std::string s;
  std::stringstream out;
  SpaceSeparator facet(1); //1 - don't delete when done
  std::locale prev = out.imbue(std::locale(std::locale(), &facet));
  out << std::setprecision(15) << f;

  s = out.str();
  std::copy(s.begin(), s.end(), str);
  int i;
  for (i=s.size();i<len;i++){
    str[i] = ' ';
  }
}

}

call from Fortran:

  use iso_c_binding

  interface
    subroutine convert(str, f, l) bind(C,name="convert")
      import
      character(c_char) :: str(*)
      real(c_double), value :: f
      integer(c_int), value :: l
    end subroutine
  end interface

  character(len=100,kind=c_char) :: ch

  call convert(ch, 123456.123_c_double, len(ch, kind=c_int))
  print *,ch
end

On my machine it prints 123 456,123:

> gfortran locale.cc locale.f90 -lstdc++
> ./a.out 
 123 456,123                                

Disclaimer: I am not a C++ programmer and he solution can be slow. Maybe the brute force approach in Fortran is better.

I used this answer as a base: https://stackoverflow.com/a/2648663/721644

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