C++ Builder控制台应用中如何正确打印String类型内容？

C++ Builder中的String默认是UnicodeString（UTF-16编码的宽字符类型），而std::cout仅支持输出ANSI窄字符（char*），直接用t_str()或c_str()返回的wchar_t*宽字符指针给std::cout输出时，会被错误解析为窄字符，导致乱码。

以下是几种可行的解决方式：

方法1：使用std::wcout输出宽字符 #

std::wcout专门用于处理宽字符输出，直接搭配String的c_str()或t_str()即可：

bool Tests::test001() {
    std::string temp;

    CDecoder decoder;
    String input = "60000000190210703800000EC00000164593560001791662000000000000080000000002104302040235313531353135313531353153414C4535313030313233343536373831323334353637383930313233";
    String expected_output = "6000000019";
    String output = decoder.getTPDU(input);
    
    std::wcout << L"Expected :" << expected_output.c_str() << std::endl;
    std::wcout << L"Obtained :" << output.c_str() << std::endl;
    
    return output == expected_output;
}

方法2：转换为ANSI字符串输出 #

如果你的字符串内容仅包含ASCII字符，可以将String转换为AnsiString后再输出：

bool Tests::test001() {
    std::string temp;

    CDecoder decoder;
    String input = "60000000190210703800000EC00000164593560001791662000000000000080000000002104302040235313531353135313531353153414C4535313030313233343536373831323334353637383930313233";
    String expected_output = "6000000019";
    String output = decoder.getTPDU(input);
    
    std::cout << "Expected :" << AnsiString(expected_output).c_str() << std::endl;
    std::cout << "Obtained :" << AnsiString(output).c_str() << std::endl;
    
    return output == expected_output;
}

方法3：配置控制台为UTF-8编码输出 #

如果需要支持非ASCII字符，可先设置控制台输出编码为UTF-8，再将String转换为UTF-8格式输出：

#include <windows.h>

bool Tests::test001() {
    // 设置控制台输出编码为UTF-8
    SetConsoleOutputCP(CP_UTF8);
    
    std::string temp;

    CDecoder decoder;
    String input = "60000000190210703800000EC00000164593560001791662000000000000080000000002104302040235313531353135313531353153414C4535313030313233343536373831323334353637383930313233";
    String expected_output = "6000000019";
    String output = decoder.getTPDU(input);
    
    std::string expected_utf8 = UTF8String(expected_output);
    std::string output_utf8 = UTF8String(output);
    
    std::cout << "Expected :" << expected_utf8.c_str() << std::endl;
    std::cout << "Obtained :" << output_utf8.c_str() << std::endl;
    
    return output == expected_output;
}

内容的提问来源于stack exchange，提问作者Beto