printf输出不受全局语言环境影响吗?

本文介绍了printf输出不受全局语言环境影响吗?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我无法在Visual C ++(VS 2005)中获得printf函数，无法以整数形式输出数千个分隔符.

I cannot get the printf functions in Visual-C++ (VS 2005) to output thousands separator in my integers.

注意:注释表明这是printf的正常行为.但是，C ++ iostream 是否将千位分隔符插入数字(已通过std::stringstream和imbue测试)，所以这纯粹是iostream的功能，并且不存在于"C"格式函数中吗?

Note: Comments indicate that this is printf's normal behaviour. However, C++ iostream does insert the thousands separator into numbers (tested with std::stringstream and imbue) so is this purely a feature of iostreams and isn't present in the "C" formatting functions?

这是测试代码:

setlocale(LC_ALL, ""); // -> User locale _locale_t loc = _create_locale(LC_ALL, ""); // -> user locale for *_l version struct lconv *pLocalSettings = localeconv(); printf("Locale is: %s\n", setlocale(LC_NUMERIC, NULL)); printf("Thousands separator set to : {%s}\n", pLocalSettings->thousands_sep); printf("Grouping set to: {%o}\n", int(pLocalSettings->grouping[0])); int i = 1000000; __int64 i64 = i * 2; printf("32 Bit integer output: %d\n", i); printf("64 Bit integer output: %I64d\n", i64); _printf_l("32 Bit integer output: %d\n", /*locale=*/loc, i); _printf_l("64 Bit integer output: %I64d\n", /*locale=*/loc, i64); _free_locale(loc);

输出为:

Locale is: German_Austria.1252 Thousands separator set to : {.} Grouping set to: {3} 32 Bit integer output: 1000000 64 Bit integer output: 2000000 32 Bit integer output: 1000000 64 Bit integer output: 2000000

进一步检查后，似乎无法正常工作.我试过了:

Upon further checking, it would appear that it doesn't work like this. I tried this:

#include <iostream> #include <clocale> using namespace std; int main() { setlocale(LC_ALL, "en_US"); // -> User locale struct lconv *pLocalSettings = localeconv(); printf("Locale is: %s\n", setlocale(LC_NUMERIC, NULL)); printf("Thousands separator set to : {%s}\n", pLocalSettings->thousands_sep); printf("Grouping set to: {%o}\n", int(pLocalSettings->grouping[0])); int i = 1000000; long long i64 = i * 2; printf("32 Bit integer output: %d\n", i); printf("64 Bit integer output: %I64d\n", i64); return 0; }

在 wwwpileonline/compile_cpp11_online.php 上(不能在那里找不到永久链接.)

on wwwpileonline/compile_cpp11_online.php (Can't find no permalink there.)

输出为:

Compiling the source code.... $g++ -std=c++11 main.cpp -o demo -lm -pthread -lgmpxx -lgmp -lreadline 2>&1 Executing the program.... $demo Locale is: en_US Thousands separator set to : {,} Grouping set to: {3} 32 Bit integer output: 1000000 64 Bit integer output: 2000000

推荐答案

让我分享在这里学到的知识:

Let me share what I learned here:

• C语言环境确实包含有关千位分隔符的信息，但此信息是完全不被printf*函数族使用 (除非您将标志扩展名 '，无论如何MSVC都不存在
• C++语言环境也包含该信息，并且iostream在格式化数字时实际上会使用该信息( numpunct方面)

• 使用setlocale设置全局C区域设置不会影响std::locale::global()

• C locale does contain the information regarding the thousands separator, but this information is not used at all by the printf* family of functions (unless you count the flag extension ', which isn't present in MSVC anyways)
• C++ locale contains the info as well, and iostreams actually make use of it when formatting numbers (numpunct facet)

• Setting the global C locale with setlocaledoes not affect the global C++ locale set by std::locale::global()

获得我格式化的数字的正确代码最终是:

The correct code to get my formatted numbers ended up being:

static std::locale user_locale(""); std::wstringstream buf; buf.imbue(user_locale); buf << some_integer;

对于某些用例，可以通过.