根据Kyle_the_hacker的----->的答案和我的额外内容。

Ubuntu

在终端 列出所有地区 语言环境-

安装所有地区 Sudo apt-get install -y locale -all

cpp Compile main。 g+ main, cpp

运行编译程序 $ . / a.o ut

结果

Zoë Saldaña played in La maldición del padre Cardona. ëèñ αω óóChloë
Zoë Saldaña played in La maldición del padre Cardona. ëèñ αω óóChloë
ZOË SALDAÑA PLAYED IN LA MALDICIÓN DEL PADRE CARDONA. ËÈÑ ΑΩ ÓÓCHLOË
ZOË SALDAÑA PLAYED IN LA MALDICIÓN DEL PADRE CARDONA. ËÈÑ ΑΩ ÓÓCHLOË
zoë saldaña played in la maldición del padre cardona. ëèñ αω óóchloë
zoë saldaña played in la maldición del padre cardona. ëèñ αω óóchloë

窗户

在cmd中运行VCVARS开发工具 "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"

编译main.cpp > cl /EHa main.cpp /D "_DEBUG" /D "_CONSOLE" /D "_UNICODE" /D "UNICODE" /std:c++17 /DYNAMICBASE "kernel32。自由”“user32。自由”“gdi32。自由”“winspool。自由”“comdlg32。自由”“advapi32。自由”“shell32。自由”“ole32。自由”“oleaut32。自由”“uuid。自由”“odbc32。自由”“odbccp32。自由“/ MTd

Compilador de optimización de C/C++ de Microsoft (R) versión 19.27.29111 para x64
(C) Microsoft Corporation. Todos los derechos reservados.

main.cpp
Microsoft (R) Incremental Linker Version 14.27.29111.0
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:main.exe
main.obj
kernel32.lib
user32.lib
gdi32.lib
winspool.lib
comdlg32.lib
advapi32.lib
shell32.lib
ole32.lib
oleaut32.lib
uuid.lib
odbc32.lib
odbccp32.lib

运行main.exe > main.exe

结果

Zoë Saldaña played in La maldición del padre Cardona. ëèñ αω óóChloë
Zoë Saldaña played in La maldición del padre Cardona. ëèñ αω óóChloë
ZOË SALDAÑA PLAYED IN LA MALDICIÓN DEL PADRE CARDONA. ËÈÑ ΑΩ ÓÓCHLOË
ZOË SALDAÑA PLAYED IN LA MALDICIÓN DEL PADRE CARDONA. ËÈÑ ΑΩ ÓÓCHLOË
zoë saldaña played in la maldición del padre cardona. ëèñ αω óóchloë
zoë saldaña played in la maldición del padre cardona. ëèñ αω óóchloë

代码main.cpp

这段代码只在Windows x64和Ubuntu Linux x64上进行了测试。

/*
 * Filename: c:\Users\x\Cpp\main.cpp
 * Path: c:\Users\x\Cpp
 * Filename: /home/x/Cpp/main.cpp
 * Path: /home/x/Cpp
 * Created Date: Saturday, October 17th 2020, 10:43:31 pm
 * Author: Joma
 *
 * No Copyright 2020
 */


#include <iostream>
#include <set>
#include <string>
#include <locale>

// WINDOWS
#if (_WIN32)
#include <Windows.h>
#include <conio.h>
#define WINDOWS_PLATFORM 1
#define DLLCALL STDCALL
#define DLLIMPORT _declspec(dllimport)
#define DLLEXPORT _declspec(dllexport)
#define DLLPRIVATE
#define NOMINMAX

//EMSCRIPTEN
#elif defined(__EMSCRIPTEN__)
#include <emscripten/emscripten.h>
#include <emscripten/bind.h>
#include <unistd.h>
#include <termios.h>
#define EMSCRIPTEN_PLATFORM 1
#define DLLCALL
#define DLLIMPORT
#define DLLEXPORT __attribute__((visibility("default")))
#define DLLPRIVATE __attribute__((visibility("hidden")))

// LINUX - Ubuntu, Fedora, , Centos, Debian, RedHat
#elif (__LINUX__ || __gnu_linux__ || __linux__ || __linux || linux)
#define LINUX_PLATFORM 1
#include <unistd.h>
#include <termios.h>
#define DLLCALL CDECL
#define DLLIMPORT
#define DLLEXPORT __attribute__((visibility("default")))
#define DLLPRIVATE __attribute__((visibility("hidden")))
#define CoTaskMemAlloc(p) malloc(p)
#define CoTaskMemFree(p) free(p)

//ANDROID
#elif (__ANDROID__ || ANDROID)
#define ANDROID_PLATFORM 1
#define DLLCALL
#define DLLIMPORT
#define DLLEXPORT __attribute__((visibility("default")))
#define DLLPRIVATE __attribute__((visibility("hidden")))

//MACOS
#elif defined(__APPLE__)
#include <unistd.h>
#include <termios.h>
#define DLLCALL
#define DLLIMPORT
#define DLLEXPORT __attribute__((visibility("default")))
#define DLLPRIVATE __attribute__((visibility("hidden")))
#include "TargetConditionals.h"
#if TARGET_OS_IPHONE && TARGET_IPHONE_SIMULATOR
#define IOS_SIMULATOR_PLATFORM 1
#elif TARGET_OS_IPHONE
#define IOS_PLATFORM 1
#elif TARGET_OS_MAC
#define MACOS_PLATFORM 1
#else

#endif

#endif



typedef std::string String;
typedef std::wstring WString;

#define EMPTY_STRING u8""s
#define EMPTY_WSTRING L""s

using namespace std::literals::string_literals;

class Strings
{
public:
    static String WideStringToString(const WString& wstr)
    {
        if (wstr.empty())
        {
            return String();
        }
        size_t pos;
        size_t begin = 0;
        String ret;

#if WINDOWS_PLATFORM
        int size;
        pos = wstr.find(static_cast<wchar_t>(0), begin);
        while (pos != WString::npos && begin < wstr.length())
        {
            WString segment = WString(&wstr[begin], pos - begin);
            size = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, &segment[0], segment.size(), NULL, 0, NULL, NULL);
            String converted = String(size, 0);
            WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, &segment[0], segment.size(), &converted[0], converted.size(), NULL, NULL);
            ret.append(converted);
            ret.append({ 0 });
            begin = pos + 1;
            pos = wstr.find(static_cast<wchar_t>(0), begin);
        }
        if (begin <= wstr.length())
        {
            WString segment = WString(&wstr[begin], wstr.length() - begin);
            size = WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, &segment[0], segment.size(), NULL, 0, NULL, NULL);
            String converted = String(size, 0);
            WideCharToMultiByte(CP_UTF8, WC_ERR_INVALID_CHARS, &segment[0], segment.size(), &converted[0], converted.size(), NULL, NULL);
            ret.append(converted);
        }
#elif LINUX_PLATFORM || MACOS_PLATFORM || EMSCRIPTEN_PLATFORM
        size_t size;
        pos = wstr.find(static_cast<wchar_t>(0), begin);
        while (pos != WString::npos && begin < wstr.length())
        {
            WString segment = WString(&wstr[begin], pos - begin);
            size = wcstombs(nullptr, segment.c_str(), 0);
            String converted = String(size, 0);
            wcstombs(&converted[0], segment.c_str(), converted.size());
            ret.append(converted);
            ret.append({ 0 });
            begin = pos + 1;
            pos = wstr.find(static_cast<wchar_t>(0), begin);
        }
        if (begin <= wstr.length())
        {
            WString segment = WString(&wstr[begin], wstr.length() - begin);
            size = wcstombs(nullptr, segment.c_str(), 0);
            String converted = String(size, 0);
            wcstombs(&converted[0], segment.c_str(), converted.size());
            ret.append(converted);
        }
#else
        static_assert(false, "Unknown Platform");
#endif
        return ret;
    }

    static WString StringToWideString(const String& str)
    {
        if (str.empty())
        {
            return WString();
        }

        size_t pos;
        size_t begin = 0;
        WString ret;
#ifdef WINDOWS_PLATFORM
        int size = 0;
        pos = str.find(static_cast<char>(0), begin);
        while (pos != std::string::npos) {
            std::string segment = std::string(&str[begin], pos - begin);
            std::wstring converted = std::wstring(segment.size() + 1, 0);
            size = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, &segment[0], segment.size(), &converted[0], converted.length());
            converted.resize(size);
            ret.append(converted);
            ret.append({ 0 });
            begin = pos + 1;
            pos = str.find(static_cast<char>(0), begin);
        }
        if (begin < str.length()) {
            std::string segment = std::string(&str[begin], str.length() - begin);
            std::wstring converted = std::wstring(segment.size() + 1, 0);
            size = MultiByteToWideChar(CP_UTF8, MB_ERR_INVALID_CHARS, segment.c_str(), segment.size(), &converted[0], converted.length());
            converted.resize(size);
            ret.append(converted);
        }

#elif LINUX_PLATFORM || MACOS_PLATFORM || EMSCRIPTEN_PLATFORM
        size_t size;
        pos = str.find(static_cast<char>(0), begin);
        while (pos != String::npos)
        {
            String segment = String(&str[begin], pos - begin);
            WString converted = WString(segment.size(), 0);
            size = mbstowcs(&converted[0], &segment[0], converted.size());
            converted.resize(size);
            ret.append(converted);
            ret.append({ 0 });
            begin = pos + 1;
            pos = str.find(static_cast<char>(0), begin);
        }
        if (begin < str.length())
        {
            String segment = String(&str[begin], str.length() - begin);
            WString converted = WString(segment.size(), 0);
            size = mbstowcs(&converted[0], &segment[0], converted.size());
            converted.resize(size);
            ret.append(converted);
        }
#else
        static_assert(false, "Unknown Platform");
#endif
        return ret;
    }


    static WString ToUpper(const WString& data)
    {
        WString result = data;
        auto& f = std::use_facet<std::ctype<wchar_t>>(std::locale());

        f.toupper(&result[0], &result[0] + result.size());
        return result;
    }

    static String  ToUpper(const String& data)
    {
        return WideStringToString(ToUpper(StringToWideString(data)));
    }

    static WString ToLower(const WString& data)
    {
        WString result = data;
        auto& f = std::use_facet<std::ctype<wchar_t>>(std::locale());
        f.tolower(&result[0], &result[0] + result.size());
        return result;
    }

    static String ToLower(const String& data)
    {
        return WideStringToString(ToLower(StringToWideString(data)));
    }

};

enum class ConsoleTextStyle
{
    DEFAULT = 0,
    BOLD = 1,
    FAINT = 2,
    ITALIC = 3,
    UNDERLINE = 4,
    SLOW_BLINK = 5,
    RAPID_BLINK = 6,
    REVERSE = 7,
};

enum class ConsoleForeground
{
    DEFAULT = 39,
    BLACK = 30,
    DARK_RED = 31,
    DARK_GREEN = 32,
    DARK_YELLOW = 33,
    DARK_BLUE = 34,
    DARK_MAGENTA = 35,
    DARK_CYAN = 36,
    GRAY = 37,
    DARK_GRAY = 90,
    RED = 91,
    GREEN = 92,
    YELLOW = 93,
    BLUE = 94,
    MAGENTA = 95,
    CYAN = 96,
    WHITE = 97
};

enum class ConsoleBackground
{
    DEFAULT = 49,
    BLACK = 40,
    DARK_RED = 41,
    DARK_GREEN = 42,
    DARK_YELLOW = 43,
    DARK_BLUE = 44,
    DARK_MAGENTA = 45,
    DARK_CYAN = 46,
    GRAY = 47,
    DARK_GRAY = 100,
    RED = 101,
    GREEN = 102,
    YELLOW = 103,
    BLUE = 104,
    MAGENTA = 105,
    CYAN = 106,
    WHITE = 107
};

class Console
{
private:
    static void EnableVirtualTermimalProcessing()
    {
#if defined WINDOWS_PLATFORM
        HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
        DWORD dwMode = 0;
        GetConsoleMode(hOut, &dwMode);
        if (!(dwMode & ENABLE_VIRTUAL_TERMINAL_PROCESSING))
        {
            dwMode |= ENABLE_VIRTUAL_TERMINAL_PROCESSING;
            SetConsoleMode(hOut, dwMode);
        }
#endif
    }

    static void ResetTerminalFormat()
    {
        std::cout << u8"\033[0m";
    }

    static void SetVirtualTerminalFormat(ConsoleForeground foreground, ConsoleBackground background, std::set<ConsoleTextStyle> styles)
    {
        String format = u8"\033[";
        format.append(std::to_string(static_cast<int>(foreground)));
        format.append(u8";");
        format.append(std::to_string(static_cast<int>(background)));
        if (styles.size() > 0)
        {
            for (auto it = styles.begin(); it != styles.end(); ++it)
            {
                format.append(u8";");
                format.append(std::to_string(static_cast<int>(*it)));
            }
        }
        format.append(u8"m");
        std::cout << format;
    }
public:
    static void Clear()
    {

#ifdef WINDOWS_PLATFORM
        std::system(u8"cls");
#elif LINUX_PLATFORM || defined MACOS_PLATFORM
        std::system(u8"clear");
#elif EMSCRIPTEN_PLATFORM
        emscripten::val::global()["console"].call<void>(u8"clear");
#else
        static_assert(false, "Unknown Platform");
#endif
    }

    static void Write(const String& s, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
    {
#ifndef EMSCRIPTEN_PLATFORM
        EnableVirtualTermimalProcessing();
        SetVirtualTerminalFormat(foreground, background, styles);
#endif
        String str = s;
#ifdef WINDOWS_PLATFORM
        WString unicode = Strings::StringToWideString(str);
        WriteConsole(GetStdHandle(STD_OUTPUT_HANDLE), unicode.c_str(), static_cast<DWORD>(unicode.length()), nullptr, nullptr);
#elif defined LINUX_PLATFORM || defined MACOS_PLATFORM || EMSCRIPTEN_PLATFORM
        std::cout << str;
#else
        static_assert(false, "Unknown Platform");
#endif

#ifndef EMSCRIPTEN_PLATFORM
        ResetTerminalFormat();
#endif
    }

    static void WriteLine(const String& s, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
    {
        Write(s, foreground, background, styles);
        std::cout << std::endl;
    }

    static void Write(const WString& s, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
    {
#ifndef EMSCRIPTEN_PLATFORM
        EnableVirtualTermimalProcessing();
        SetVirtualTerminalFormat(foreground, background, styles);
#endif
        WString str = s;

#ifdef WINDOWS_PLATFORM
        WriteConsole(GetStdHandle(STD_OUTPUT_HANDLE), str.c_str(), static_cast<DWORD>(str.length()), nullptr, nullptr);
#elif LINUX_PLATFORM || MACOS_PLATFORM || EMSCRIPTEN_PLATFORM
        std::cout << Strings::WideStringToString(str);
#else
        static_assert(false, "Unknown Platform");
#endif

#ifndef EMSCRIPTEN_PLATFORM
        ResetTerminalFormat();
#endif
    }

    static void WriteLine(const WString& s, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
    {
        Write(s, foreground, background, styles);
        std::cout << std::endl;
    }

    static void WriteLine()
    {
        std::cout << std::endl;
    }

    static void Pause()
    {
        char c;
        do
        {
            c = getchar();
            std::cout << "Press Key " << std::endl;
        } while (c != 64);
        std::cout << "KeyPressed" << std::endl;
    }

    static int PauseAny(bool printWhenPressed = false, ConsoleForeground foreground = ConsoleForeground::DEFAULT, ConsoleBackground background = ConsoleBackground::DEFAULT, std::set<ConsoleTextStyle> styles = {})
    {
        int ch;
#ifdef WINDOWS_PLATFORM
        ch = _getch();
#elif LINUX_PLATFORM || MACOS_PLATFORM || EMSCRIPTEN_PLATFORM
        struct termios oldt, newt;
        tcgetattr(STDIN_FILENO, &oldt);
        newt = oldt;
        newt.c_lflag &= ~(ICANON | ECHO);
        tcsetattr(STDIN_FILENO, TCSANOW, &newt);
        ch = getchar();
        tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
#else
        static_assert(false, "Unknown Platform");
#endif
        if (printWhenPressed)
        {
            Console::Write(String(1, ch), foreground, background, styles);
        }
        return ch;
    }
};



int main()
{
    std::locale::global(std::locale(u8"en_US.UTF-8"));
    String dataStr = u8"Zoë Saldaña played in La maldición del padre Cardona. ëèñ αω óóChloë";
    WString dataWStr = L"Zoë Saldaña played in La maldición del padre Cardona. ëèñ αω óóChloë";
    std::string locale = u8"";
    //std::string locale = u8"de_DE.UTF-8";
    //std::string locale = u8"en_US.UTF-8";
    Console::WriteLine(dataStr);
    Console::WriteLine(dataWStr);
    dataStr = Strings::ToUpper(dataStr);
    dataWStr = Strings::ToUpper(dataWStr);
    Console::WriteLine(dataStr);
    Console::WriteLine(dataWStr);
    dataStr = Strings::ToLower(dataStr);
    dataWStr = Strings::ToLower(dataWStr);
    Console::WriteLine(dataStr);
    Console::WriteLine(dataWStr);
    
    
    Console::WriteLine(u8"Press any key to exit"s, ConsoleForeground::DARK_GRAY);
    Console::PauseAny();

    return 0;
}

不使用任何库:

std::string YourClass::Uppercase(const std::string & Text)
{
    std::string UppperCaseString;
    UppperCaseString.reserve(Text.size());
    for (std::string::const_iterator it=Text.begin(); it<Text.end(); ++it)
    {
        UppperCaseString.push_back(((0x60 < *it) && (*it < 0x7B)) ? (*it - static_cast<char>(0x20)) : *it);
    }
    return UppperCaseString;
}

//works for ASCII -- no clear advantage over what is already posted...

std::string toupper(const std::string & s)
{
    std::string ret(s.size(), char());
    for(unsigned int i = 0; i < s.size(); ++i)
        ret[i] = (s[i] <= 'z' && s[i] >= 'a') ? s[i]-('a'-'A') : s[i];
    return ret;
}

我的解决方案(清除第6位):

#include <ctype.h>

inline void toupper(char* str)
{
    while (str[i]) {
        if (islower(str[i]))
            str[i] &= ~32; // Clear bit 6 as it is what differs (32) between Upper and Lowercases
        i++;
    }
}

struct convert {
   void operator()(char& c) { c = toupper((unsigned char)c); }
};

// ... 
string uc_str;
for_each(uc_str.begin(), uc_str.end(), convert());

注意:顶部解决方案的几个问题:

21.5以空结束的序列实用程序 这些头文件的内容应该与标准C库头文件相同<ctype.h>， <wctype.h>， <string.h>， <wchar.h>，和<stdlib.h>[…]

这意味着cctype成员很可能是不适合在标准算法中直接使用的宏。 同一个例子的另一个问题是，它没有强制转换实参，也没有验证它是非负的;这对于使用纯char符号的系统尤其危险。(原因是:如果这是作为一个宏实现的，它可能会使用一个查找表和你的参数索引到那个表。负指数会给你UB。)

这是c++ 11的最新代码

std::string cmd = "Hello World";
for_each(cmd.begin(), cmd.end(), [](char& in){ in = ::toupper(in); });