一个简单的类，用于将数字转换为带有千位分隔符的字符串

Shaun Harrington

4.18/5 (9投票s)

2006 年 7 月 26 日

CPOL

2分钟阅读

90523

224

一个简单的类，用于将数值转换为带有本地化千位分隔符的字符串。

下载演示项目 - 22.8 Kb

引言

这个 CTextNumber 类我已经用了好几年了。几乎在我参与的每个项目中都用到了它。最近，我发现自己正在更新 CTextNumber，于是我决定顺便分享一下。它仍然是一个非常简单的实现，我希望其他人的代码审查能帮助加强它。

作为一个 C++ 代码示例，CTextNumber 展示了操作符重载的一个良好应用。

CTextNumber 通过使用 TCHAR 类型支持 UNICODE 和 MBCS 构建。CTextNumber 仅依赖于 RTL。通过对几行代码进行更改，CTextNumber 可以转换以在 CE 上运行。MFC 仅用于演示应用程序。

Using

提取下载内容后，您必须构建项目，然后运行其输出以查看工作示例。查看 txtnum.h 和 txtnum.cpp 文件以检查 CTextNumber 类。查看 testtextnum 子文件夹中的 testtextnumDlg.cpp，了解使用 CTextNumber 的示例。您可以将指针分配给静态的 CTextNumber::s_lpNumberFormat 成员来控制格式化。以下是演示应用程序中 InitDialog() 方法中的一个代码片段。对话框类将 m_lbNumbers 定义为 MFC 的 CListBox。

// Setup for locale... you only have to do this once.

numberformat = {0};
TCHAR bufILZero[3] = {0};
GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_ILZERO, bufILZero, 3);
numberformat.LeadingZero = _ttoi(bufILZero);
TCHAR bufINegNum[3] = {0};
GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_INEGNUMBER, bufINegNum, 3);
numberformat.NegativeOrder = _ttoi(bufINegNum);
numberformat.Grouping = 3;
TCHAR bufSThousands[5] = {0};
GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_STHOUSAND, bufSThousands, 5);
numberformat.lpThousandSep = bufSThousands;
TCHAR bufSDecimal[5] = {0};
GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_SDECIMAL, bufSDecimal, 5);
numberformat.lpDecimalSep = bufSDecimal;
numberformat.NumDigits = 0;
CTextNumber::s_lpNumberFormat = &numberformat;

CString strOut;
CTextNumber tn;
// __int8                –128 to 127

// unsigned __int8        0 to 255

signed __int8 i8 = 0;
tn = i8;
strOut.Format(TEXT("INT8 value of 0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i8 = 1;
strOut.Format(TEXT("INT8 value of 1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i8 = -1;
strOut.Format(TEXT("INT8 value of -1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i8 = SCHAR_MAX;
strOut.Format(TEXT("INT8 value of SCHAR_MAX = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i8 = SCHAR_MIN;
strOut.Format(TEXT("INT8 value of SCHAR_MIN = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);

unsigned __int8 ui8 = 0;
tn = ui8;
strOut.Format(TEXT("UINT8 value of 0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui8 = 1;
strOut.Format(TEXT("UINT8 value of 1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui8 = -1;
strOut.Format(TEXT("UINT8 value of -1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui8 = UCHAR_MAX;
strOut.Format(TEXT("UINT8 value of UCHAR_MAX = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);

// __int16                –32,768 to 32,767

// unsigned __int16        0 to 65,535

signed __int16 i16 = 0;
tn = i16;
strOut.Format(TEXT("INT16 value of 0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i16 = 1;
strOut.Format(TEXT("INT16 value of 1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i16 = -1;
strOut.Format(TEXT("INT16 value of -1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i16 = SHRT_MAX;
strOut.Format(TEXT("INT16 value of SHRT_MAX = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i16 = SHRT_MIN;
strOut.Format(TEXT("INT16 value of SHRT_MIN = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);

unsigned __int16 ui16 = 0;
tn = ui16;
strOut.Format(TEXT("UINT16 value of 0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui16 = 1;
strOut.Format(TEXT("UINT16 value of 1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui16 = -1;
strOut.Format(TEXT("UINT16 value of -1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui16 = USHRT_MAX;
strOut.Format(TEXT("UINT16 value of USHRT_MAX = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);

// __int32                –2,147,483,648 to 2,147,483,647 

// unsigned __int32        0 to 4,294,967,295

signed __int32 i32 = 0;
tn = i32;
strOut.Format(TEXT("INT32 value of 0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i32 = 1;
strOut.Format(TEXT("INT32 value of 1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i32 = -1;
strOut.Format(TEXT("INT32 value of -1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i32 = LONG_MAX;
strOut.Format(TEXT("INT32 value of LONG_MAX = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i32 = LONG_MIN;
strOut.Format(TEXT("INT32 value of LONG_MIN = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);

unsigned __int32 ui32 = 0;
tn = ui32;
strOut.Format(TEXT("UINT32 value of 0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui32 = 1;
strOut.Format(TEXT("UINT32 value of 1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui32 = -1;
strOut.Format(TEXT("UINT32 value of -1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = ui32 = ULONG_MAX;
strOut.Format(TEXT("UINT32 value of ULONG_MAX = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);

// __int64  –9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 

// unsigned __int64        0 to 18446744073709551615 

__int64 i64 = 0;
tn = i64;
strOut.Format(TEXT("INT64 value of 0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i64 = 1;
strOut.Format(TEXT("INT64 value of 1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i64 = -1;
strOut.Format(TEXT("INT64 value of -1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i64 = _I64_MAX;
strOut.Format(TEXT("INT64 value of _I64_MAX = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = i64 = _I64_MIN;
strOut.Format(TEXT("INT64 value of _I64_MIN = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);

unsigned __int64 u64 = 0;
tn = u64;
strOut.Format(TEXT("UINT64 value of 0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = u64 = 1;
strOut.Format(TEXT("UINT64 value of 1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = u64 = -1;
strOut.Format(TEXT("UINT64 value of -1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = u64 = _UI64_MAX;
strOut.Format(TEXT("UINT64 value of _UI64_MAX = %s"), 
                   tn.GetString());
m_lbNumbers.AddString(strOut);
tn = u64 = 9999999999999999999;
strOut.Format(TEXT("UINT64 value of " + 
              "9999999999999999999 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = u64 = 0x8ac7230489e7ffff;
strOut.Format(TEXT("UINT64 value " + 
              "of 0x8ac7230489e7ffff = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);


numberformat.NumDigits = 1;
float fVal = 0.0f;
tn = fVal;
strOut.Format(TEXT("float value of 0.0 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
tn = fVal = 1.1f;
strOut.Format(TEXT("float value of 1.1 = %s"), tn.GetString());
m_lbNumbers.AddString(strOut);
numberformat.NumDigits = 2;
tn = fVal = 11.11f;
strOut.Format(TEXT("float value of 11.11 = %s"), 
                   tn.GetString());
m_lbNumbers.AddString(strOut);
numberformat.NumDigits = 3;
tn = fVal = 111.111f;
strOut.Format(TEXT("float value of 111.111 = %s"), 
                   tn.GetString());
m_lbNumbers.AddString(strOut);
numberformat.NumDigits = 4;
tn = fVal = 1111.1111f;
strOut.Format(TEXT("float value of 1111.1111 = %s"), 
                   tn.GetString());
m_lbNumbers.AddString(strOut);
numberformat.NumDigits = 5;
tn = fVal = 11111.11111f;
strOut.Format(TEXT("float value of 11111.11111 = %s"), 
                   tn.GetString());
m_lbNumbers.AddString(strOut);
numberformat.NumDigits = 6;
tn = fVal = 111111.111111f;
strOut.Format(TEXT("float value of 111111.111111 = %s"), 
                   tn.GetString());
m_lbNumbers.AddString(strOut);

numberformat.NumDigits = 2;
tn = fVal = 3.4E+38f;
strOut.Format(TEXT("float value of 3.4E+38f = %s"), 
                   tn.GetString());
m_lbNumbers.AddString(strOut);

double dbVal = 0.0;
tn = dbVal = 1.7E+308;
strOut.Format(TEXT("double value of 1.7E+308 = %s"), 
                   tn.GetString());
m_lbNumbers.AddString(strOut);

CString str;
CSize   sz;
int     dx = 0;
CDC*    pDC = m_lbNumbers.GetDC();
for(int i=0; i < m_lbNumbers.GetCount(); i++) {
    m_lbNumbers.GetText( i, str );
    sz = pDC->GetTextExtent(str);
    if(sz.cx > dx)
        dx = sz.cx;
}
m_lbNumbers.ReleaseDC(pDC);
m_lbNumbers.SetHorizontalExtent(dx);

（图 1. 使用该类）

Demo image

（图 2. 演示输出）

类内部

/*static*/ LPNUMBERFMT CTextNumber::s_lpNumberFormat = NULL;

#define INT8BUFSIZE  10
#define INT16BUFSIZE 20
#define INT32BUFSIZE 20
#define INT64BUFSIZE 40

void CTextNumber::operator=(signed __int8& i8Val) {
    TCHAR numBuffer[INT8BUFSIZE+1] = {0};
    _itot_s(i8Val, numBuffer, INT8BUFSIZE, 10 );
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, INT8BUFSIZE);
}

void CTextNumber::operator=(unsigned __int8& u8Val) {
    TCHAR numBuffer[INT8BUFSIZE+1] = {0};
    _itot_s(u8Val, numBuffer, INT8BUFSIZE, 10 );
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, INT8BUFSIZE);
}

void CTextNumber::operator=(__int16& i16Val) {
    TCHAR numBuffer[INT16BUFSIZE+1] = {0};
    _itot_s(i16Val, numBuffer, INT16BUFSIZE, 10 );
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, INT16BUFSIZE);
}

void CTextNumber::operator=(unsigned __int16& u16Val) {
    TCHAR numBuffer[INT16BUFSIZE+1] = {0};
    _itot_s(u16Val, numBuffer, INT16BUFSIZE, 10 );
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, INT16BUFSIZE);
}

void CTextNumber::operator=(__int32& i32Val) {
    TCHAR numBuffer[INT32BUFSIZE+1] = {0};
    _itot_s(i32Val, numBuffer, INT32BUFSIZE, 10 );
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, INT32BUFSIZE);
}

void CTextNumber::operator=(unsigned __int32& u32Val) {
    TCHAR numBuffer[INT32BUFSIZE+1] = {0};
    _ultow_s(u32Val, numBuffer, 10 );
    GetNumberFormat(LOCALE_USER_DEFAULT, 0, numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, INT32BUFSIZE);
}

void CTextNumber::operator=(__int64& i64Val) {
    TCHAR numBuffer[INT64BUFSIZE+1] = {0};
    _i64tot_s(i64Val, numBuffer, INT64BUFSIZE, 10 );
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, INT64BUFSIZE);
}

void CTextNumber::operator=(unsigned __int64& u64Val) {
    TCHAR numBuffer[INT64BUFSIZE+1] = {0};
    _ui64tot_s(u64Val, numBuffer, INT64BUFSIZE, 10 );
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, INT64BUFSIZE);
}

void CTextNumber::operator=(float& fVal) {
    TCHAR numBuffer[_CVTBUFSIZE+1] = {0};
    TCHAR bufFormatter[20] = TEXT("%f");
    if(s_lpNumberFormat) {
        _stprintf_s(bufFormatter, 20, TEXT("%%.%df"), 
                    s_lpNumberFormat->NumDigits);
    }
    _stprintf_s(numBuffer, _CVTBUFSIZE, bufFormatter, fVal);
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, _CVTBUFSIZE);
}

void CTextNumber::operator=(double& dbVal) {
    TCHAR numBuffer[(_CVTBUFSIZE*2)+1] = {0};
    TCHAR bufFormatter[20] = TEXT("%f");
    if(s_lpNumberFormat) {
        _stprintf_s(bufFormatter, 20, TEXT("%%.%df"), 
                    s_lpNumberFormat->NumDigits);
    }
    _stprintf_s(numBuffer, (_CVTBUFSIZE*2), bufFormatter, dbVal);
    GetNumberFormat(LOCALE_USER_DEFAULT, 0,  numBuffer, 
                    s_lpNumberFormat, m_lpcBuffer, (_CVTBUFSIZE*2));
}

（图 3. 类代码）

替代方案

这是一个使用流来完成相同输出的代码块。Richard Taylor 让我了解了这一点，我不得不说，在允许依赖 STL 的情况下，我更喜欢它胜过我的类。

#include <locale>

#include <string>

#include <sstream>

#include <iomanip>

using namespace std;

void CtesttextnumDlg::DoSTLMethod() {
    wostringstream oss;

    // Setup for locale... you only have to do this once.

    locale localeUS( "English_USA" );
    oss.imbue( localeUS );

    signed __int8 i8 = 0;
    oss << _T("INT8 value of 0 = ") << i8;
    m_lbNumbers.AddString(oss.str().c_str());
    i8 = 1;
    oss.str( _T("") );
    oss << _T("INT8 value of 1 = ") << i8;
    m_lbNumbers.AddString(oss.str().c_str());
    i8 = -1;
    oss.str( _T("") );
    oss << _T("INT8 value of -1 = ") << i8;
    m_lbNumbers.AddString(oss.str().c_str());
    i8 = SCHAR_MAX;
    oss.str( _T("") );
    oss << _T("INT8 value of SCHAR_MAX = ") << i8;
    m_lbNumbers.AddString(oss.str().c_str());
    i8 = SCHAR_MIN;
    oss.str( _T("") );
    oss << _T("INT8 value of SCHAR_MIN = ") << i8;
    m_lbNumbers.AddString(oss.str().c_str());

    unsigned __int8 ui8 = 0;
    oss.str( _T("") );
    oss << _T("UINT8 value of 0 = ") << ui8;
    m_lbNumbers.AddString(oss.str().c_str());
    ui8 = 1;
    oss.str( _T("") );
    oss << _T("UINT8 value of 1 = ") << ui8;
    m_lbNumbers.AddString(oss.str().c_str());
    ui8 = -1;
    oss.str( _T("") );
    oss << _T("UINT8 value of -1 = ") << ui8;
    m_lbNumbers.AddString(oss.str().c_str());
    ui8 = UCHAR_MAX;
    oss.str( _T("") );
    oss << _T("UINT8 value of UCHAR_MAX = ") << ui8;
    m_lbNumbers.AddString(oss.str().c_str());

    // __int16                –32,768 to 32,767

    // unsigned __int16        0 to 65,535

    signed __int16 i16 = 0;
    oss.str( _T("") );
    oss << _T("INT16 value of 0 = ") << i16;
    m_lbNumbers.AddString(oss.str().c_str());
    i16 = 1;
    oss.str( _T("") );
    oss << _T("INT16 value of 1 = ") << i16;
    m_lbNumbers.AddString(oss.str().c_str());
    i16 = -1;
    oss.str( _T("") );
    oss << _T("INT16 value of -1 = ") << i16;
    m_lbNumbers.AddString(oss.str().c_str());
    i16 = SHRT_MAX;
    oss.str( _T("") );
    oss << _T("INT16 value of SHRT_MAX = ") << i16;
    m_lbNumbers.AddString(oss.str().c_str());
    i16 = SHRT_MIN;
    oss.str( _T("") );
    oss << _T("INT16 value of SHRT_MIN = ") << i16;
    m_lbNumbers.AddString(oss.str().c_str());

    unsigned __int16 ui16 = 0;
    oss.str( _T("") );
    oss << _T("UINT16 value of 0 = ") << ui16;
    m_lbNumbers.AddString(oss.str().c_str());
    ui16 = 1;
    oss.str( _T("") );
    oss << _T("UINT16 value of 1 = ") << ui16;
    m_lbNumbers.AddString(oss.str().c_str());
    ui16 = -1;
    oss.str( _T("") );
    oss << _T("UINT16 value of -1 = ") << ui16;
    m_lbNumbers.AddString(oss.str().c_str());
    ui16 = USHRT_MAX;
    oss.str( _T("") );
    oss << _T("UINT16 value of USHRT_MAX = ") << ui16;
    m_lbNumbers.AddString(oss.str().c_str());

    // __int32                –2,147,483,648 to 2,147,483,647 

    // unsigned __int32        0 to 4,294,967,295

    signed __int32 i32 = 0;
    oss.str( _T("") );
    oss << _T("INT32 value of 0 = ") << i32;
    m_lbNumbers.AddString(oss.str().c_str());
    i32 = 1;
    oss.str( _T("") );
    oss << _T("INT32 value of 1 = ") << i32;
    m_lbNumbers.AddString(oss.str().c_str());
    i32 = -1;
    oss.str( _T("") );
    oss << _T("INT32 value of -1 = ") << i32;
    m_lbNumbers.AddString(oss.str().c_str());
    i32 = LONG_MAX;
    oss.str( _T("") );
    oss << _T("INT32 value of LONG_MAX = ") << i32;
    m_lbNumbers.AddString(oss.str().c_str());
    i32 = LONG_MIN;
    oss.str( _T("") );
    oss << _T("INT32 value of LONG_MIN = ") << i32;
    m_lbNumbers.AddString(oss.str().c_str());

    unsigned __int32 ui32 = 0;
    oss.str( _T("") );
    oss << _T("UINT32 value of 0 = ") << ui32;
    m_lbNumbers.AddString(oss.str().c_str());
    ui32 = 1;
    oss.str( _T("") );
    oss << _T("UINT32 value of 1 = ") << ui32;
    m_lbNumbers.AddString(oss.str().c_str());
    ui32 = -1;
    oss.str( _T("") );
    oss << _T("UINT32 value of -1 = ") << ui32;
    m_lbNumbers.AddString(oss.str().c_str());
    ui32 = ULONG_MAX;
    oss.str( _T("") );
    oss << _T("UINT32 value of ULONG_MAX = ") << ui32;
    m_lbNumbers.AddString(oss.str().c_str());

    // __int64  –9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 

    // unsigned __int64  0 to 18446744073709551615 

    __int64 i64 = 0;
    oss.str( _T("") );
    oss << _T("INT64 value of 0 = ") << i64;
    m_lbNumbers.AddString(oss.str().c_str());
    i64 = 1;
    oss.str( _T("") );
    oss << _T("INT64 value of 1 = ") << i64;
    m_lbNumbers.AddString(oss.str().c_str());
    i64 = -1;
    oss.str( _T("") );
    oss << _T("INT64 value of -1 = ") << i64;
    m_lbNumbers.AddString(oss.str().c_str());
    i64 = _I64_MAX;
    oss.str( _T("") );
    oss << _T("INT64 value of _I64_MAX = ") << i64;
    m_lbNumbers.AddString(oss.str().c_str());
    i64 = _I64_MIN;
    oss.str( _T("") );
    oss << _T("INT64 value of _I64_MIN = ") << i64;
    m_lbNumbers.AddString(oss.str().c_str());

    unsigned __int64 u64 = 0;
    oss.str( _T("") );
    oss << _T("UINT64 value of 0 = ") << u64;
    m_lbNumbers.AddString(oss.str().c_str());
    u64 = 1;
    oss.str( _T("") );
    oss << _T("UINT64 value of 1 = ") << u64;
    m_lbNumbers.AddString(oss.str().c_str());
    u64 = -1;
    oss.str( _T("") );
    oss << _T("UINT64 value of -1 = ") << u64;
    m_lbNumbers.AddString(oss.str().c_str());
    u64 = _UI64_MAX;
    oss.str( _T("") );
    oss << _T("UINT64 value of _UI64_MAX = ") << u64;
    m_lbNumbers.AddString(oss.str().c_str());

    u64 = 9999999999999999999;
    oss.str( _T("") );
    oss << _T("UINT64 value of 9999999999999999999 = ") << u64;
    m_lbNumbers.AddString(oss.str().c_str());
    u64 = 0x8ac7230489e7ffff;
    oss.str( _T("") );
    oss << _T("UINT64 value of 0x8ac7230489e7ffff = ") << u64;
    m_lbNumbers.AddString(oss.str().c_str());

    float fVal = 0.0f;
    oss.str( _T("") );
    oss << _T("float value of 0.0f = ") 
        << std::setprecision(2) << fVal;
    m_lbNumbers.AddString(oss.str().c_str());
    fVal = 1.1f;
    oss.str( _T("") );
    oss << _T("float value of 1.1f = ") << fVal;
    fVal = 11.11f;
    oss.str( _T("") );
    oss << _T("float value of 11.11f = ") 
        << std::fixed << std::setprecision(2) 
        << std::showpoint << fVal;
    m_lbNumbers.AddString(oss.str().c_str());
    fVal = 111.111f;
    oss.str( _T("") );
    oss << _T("float value of 111.111f = ") 
        << std::fixed << std::setprecision(3) 
        << std::showpoint << fVal;
    m_lbNumbers.AddString(oss.str().c_str());
    fVal = 1111.1111f;
    oss.str( _T("") );
    oss << _T("float value of 1111.1111f = ") 
        << std::fixed << std::setprecision(4) 
        << std::showpoint << fVal;
    m_lbNumbers.AddString(oss.str().c_str());
    fVal = 11111.11111f;
    oss.str( _T("") );
    oss << _T("float value of 11111.11111f = ") 
        << std::fixed << std::setprecision(5) 
        << std::showpoint << fVal;
    m_lbNumbers.AddString(oss.str().c_str());
    fVal = 111111.111111f;
    oss.str( _T("") );
    oss << _T("float value of 111111.111111f = ") 
        << std::fixed << std::setprecision(6) 
        << std::showpoint << fVal;
    m_lbNumbers.AddString(oss.str().c_str());

    fVal = 3.4E+38f;
    oss.str( _T("") );
    oss << _T("float value of 3.4E+38f = ") 
        << std::fixed << std::setprecision(2) 
        << std::showpoint << fVal;
    m_lbNumbers.AddString(oss.str().c_str());

    double dbVal = 0.0;
    dbVal = 1.7E+308;
    oss.str( _T("") );
    oss << _T("double value of 1.7E+308 = ") 
        << std::fixed << std::setprecision(2) 
        << std::showpoint << dbVal;
    m_lbNumbers.AddString(oss.str().c_str());
}

Demo image

（图 3. STL 演示输出）

摘要

如果我遗漏了任何你认为应该在文章中提及的细节，请告诉我。

如果你能花一秒钟时间来评价这篇文章，甚至留下评论，将不胜感激。

感谢阅读！

历史

2006 年 8 月 9 日：修复了导致具有最大值的 double 错误转换的错误。
2006 年 7 月 27 日：现在使用 GetNumberFormat；增加了对 float 和 double 的支持。
2006 年 7 月 27 日：在第一个帖子中，__int32 转换存在一个错误，并且不支持 __int16 ...现在都已修复。