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Posted on 2008-12-05 19:08 Thinkfeng 阅读(412) 评论(0) 编辑 收藏 引用
1 int i = 100;
2long l = 2001;
3float f=300.2;
4double d=12345.119;
5char username[]="程佩君";
6char temp[200];
7char *buf;
8CString str;
9_variant_t v1;
10_bstr_t v2;
11
一、其它数据类型转换为字符串
1短整型(int)
2  itoa(i,temp,10);/**////将i转换为字符串放入temp中,最后一个数字表示十进制 3itoa(i,temp,2); /**////按二进制方式转换 4长整型(long)
5ltoa(l,temp,10);
6浮点数(float,double)
7用fcvt可以完成转换,这是MSDN中的例子:
8int decimal, sign;
9char *buffer;
10double source = 3.1415926535;
11buffer = _fcvt( source, 7, &decimal, &sign );
12运行结果:source: 3.1415926535 buffer: '31415927' decimal: 1 sign: 0
13decimal表示小数点的位置,sign表示符号:0为正数，1为负数
14CString变量
15str = "2008北京奥运";
16buf = (LPSTR)(LPCTSTR)str;
17BSTR变量
18BSTR bstrValue = ::SysAllocString(L"程序员");
19char * buf = _com_util::ConvertBSTRToString(bstrValue);
20SysFreeString(bstrValue);
21AfxMessageBox(buf);
22delete(buf);
23CComBSTR变量
24CComBSTR bstrVar("test");
25char *buf = _com_util::ConvertBSTRToString(bstrVar.m_str);
26AfxMessageBox(buf);
27delete(buf);
28
29_bstr_t变量
30_bstr_t类型是对BSTR的封装，因为已经重载了=操作符，所以很容易使用
31_bstr_t bstrVar("test");
32const char *buf = bstrVar;/**////不要修改buf中的内容 33AfxMessageBox(buf);
34
35
36通用方法(针对非COM数据类型)
37用sprintf完成转换
38
39char buffer[200]; char c = '1'; int i = 35; long j = 1000; float f = 1.7320534f; sprintf( buffer, "%c",c); sprintf( buffer, "%d",i); sprintf( buffer, "%d",j); sprintf( buffer, "%f",f);
40
二、字符串转换为其它数据类型
1strcpy(temp,"123");
2
3短整型(int)
4i = atoi(temp);
5长整型(long)
6l = atol(temp);
7浮点(double)
8d = atof(temp);
9CString变量
10CString name = temp;
11BSTR变量
12BSTR bstrValue = ::SysAllocString(L"程序员");
13 /**////完成对bstrValue的使用14SysFreeString(bstrValue);
15
16CComBSTR变量
17CComBSTR类型变量可以直接赋值
18CComBSTR bstrVar1("test");
19CComBSTR bstrVar2(temp);
20
21_bstr_t变量
22_bstr_t类型的变量可以直接赋值
23_bstr_t bstrVar1("test");
24_bstr_t bstrVar2(temp);
25
三、其它数据类型转换到CString
1使用CString的成员函数Format来转换,例如:
2
3
4整数(int)
5str.Format("%d",i);
6浮点数(float)
7str.Format("%f",i);
8字符串指针(char *)等已经被CString构造函数支持的数据类型可以直接赋值
9str = username;
10对于Format所不支持的数据类型，可以通过上面所说的关于其它数据类型转化到char *的方法先转到char *，然后赋值给CString变量。
四、BSTR、_bstr_t与CComBSTR
1CComBSTR 是ATL对BSTR的封装，_bstr_t是C++对BSTR的封装,BSTR是32位指针,但并不直接指向字串的缓冲区。
2char *转换到BSTR可以这样:
3BSTR b=_com_util::ConvertStringToBSTR("数据");/**////使用前需要加上comutil.h和comsupp.lib 4SysFreeString(bstrValue);
5反之可以使用
6char *p=_com_util::ConvertBSTRToString(b);
7delete p;
8具体可以参考一，二段落里的具体说明。
9
10CComBSTR与_bstr_t对大量的操作符进行了重载，可以直接进行=,!=,==等操作，所以使用非常方便。
11特别是_bstr_t,建议大家使用它。
五、VARIANT 、_variant_t 与 COleVariant
1VARIANT的结构可以参考头文件VC98\Include\OAIDL.H中关于结构体tagVARIANT的定义。
2对于VARIANT变量的赋值：首先给vt成员赋值，指明数据类型，再对联合结构中相同数据类型的变量赋值，举个例子：
3VARIANT va;
4int a=2001;
5va.vt=VT_I4;/**////指明整型数据 6va.lVal=a; /**////赋值 7
8
9_variant_t是VARIANT的封装类，其赋值可以使用强制类型转换，其构造函数会自动处理这些数据类型。
10使用时需加上#include <comdef.h>
11例如：
12long l=222;
13ing i=100;
14_variant_t lVal(l);
15lVal = (long)i;
16
17COleVariant的使用与_variant_t的方法基本一样，请参考如下例子：
18COleVariant v3 = "字符串", v4 = (long)1999;
19CString str =(BSTR)v3.pbstrVal;
20long i = v4.lVal;
21
22/**/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// 23本主题演示如何将各种 C++ 字符串类型转换为其他字符串。可以转换的字符串类型包括 char *、wchar_t*、_bstr_t、CComBSTR、CString、basic_string 和 System.String。在所有情况下，在将字符串转换为新类型时，都会创建字符串的副本。对新字符串进行的任何更改都不会影响原始字符串，反之亦然。
24
25
从 char * 转换
1//此示例演示如何从 char * 转换为上面列出的其他字符串类型。
2// convert_from_char.cpp
3// compile with /clr /link comsuppw.lib
4#include <iostream>
5include <stdlib.h>#include <string>
6#include "atlbase.h"#include "atlstr.h"#include "comutil.h"
7using namespace std;using namespace System;
8int main(){ char *orig = "Hello, World!"; cout << orig << " (char *)" << endl;
9 // Convert to a wchar_t* size_t origsize = strlen(orig) + 1; const size_t newsize = 100; size_t convertedChars = 0; wchar_t wcstring[newsize]; mbstowcs_s(&convertedChars, wcstring, origsize, orig, _TRUNCATE); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl;
10 // Convert to a _bstr_t _bstr_t bstrt(orig); bstrt += " (_bstr_t)"; cout << bstrt << endl;
11 // Convert to a CComBSTR CComBSTR ccombstr(orig); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; }
12 // Convert to a CString CString cstring(orig); cstring += " (CString)"; cout << cstring << endl;
13 // Convert to a basic_string string basicstring(orig); basicstring += " (basic_string)"; cout << basicstring << endl;
14 // Convert to a System::String String ^systemstring = gcnew String(orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;}
1//输出
2Hello, World! (char *)
3Hello, World! (wchar_t *)
4Hello, World! (_bstr_t)
5Hello, World! (CComBSTR)
6Hello, World! (CString)
7Hello, World! (basic_string)
8Hello, World! (System::String)
从 wchar_t * 转换
1此示例演示如何从 wchar_t * 转换为上面列出的其他字符串类型。
2
3// convert_from_wchar_t.cpp// compile with /clr /link comsuppw.lib
4#include <iostream>#include <stdlib.h>#include <string>
5#include "atlbase.h"#include "atlstr.h"#include "comutil.h"
6using namespace std;using namespace System;
7int main(){ wchar_t *orig = L"Hello, World!"; wcout << orig << L" (wchar_t *)" << endl;
8 // Convert to a char* size_t origsize = wcslen(orig) + 1; const size_t newsize = 100; size_t convertedChars = 0; char nstring[newsize]; wcstombs_s(&convertedChars, nstring, origsize, orig, _TRUNCATE); strcat_s(nstring, " (char *)"); cout << nstring << endl;
9 // Convert to a _bstr_t _bstr_t bstrt(orig); bstrt += " (_bstr_t)"; cout << bstrt << endl;
10 // Convert to a CComBSTR CComBSTR ccombstr(orig); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; }
11 // Convert to a CString CString cstring(orig); cstring += " (CString)"; cout << cstring << endl;
12 // Convert to a basic_string wstring basicstring(orig); basicstring += L" (basic_string)"; wcout << basicstring << endl;
13 // Convert to a System::String String ^systemstring = gcnew String(orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;}
14//输出
15Hello, World! (wchar_t *)Hello, World! (char *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (basic_string)Hello, World! (System::String)
1从 _bstr_t 转换
2
3
4示例
5
6说明
7此示例演示如何从 _bstr_t 转换为上面列出的其他字符串类型。
8
9// convert_from_bstr_t.cpp// compile with /clr /link comsuppw.lib
10#include <iostream>#include <stdlib.h>#include <string>
11#include "atlbase.h"#include "atlstr.h"#include "comutil.h"
12using namespace std;using namespace System;
13int main(){ _bstr_t orig("Hello, World!"); wcout << orig << " (_bstr_t)" << endl;
14 // Convert to a char* const size_t newsize = 100; char nstring[newsize]; strcpy_s(nstring, (char *)orig); strcat_s(nstring, " (char *)"); cout << nstring << endl;
15 // Convert to a wchar_t* wchar_t wcstring[newsize]; wcscpy_s(wcstring, (wchar_t *)orig); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl;
16 // Convert to a CComBSTR CComBSTR ccombstr((char *)orig); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; }
17 // Convert to a CString CString cstring((char *)orig); cstring += " (CString)"; cout << cstring << endl;
18 // Convert to a basic_string string basicstring((char *)orig); basicstring += " (basic_string)"; cout << basicstring << endl;
19 // Convert to a System::String String ^systemstring = gcnew String((char *)orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 输出
20Hello, World! (_bstr_t)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (basic_string)Hello, World! (System::String)
21从 CComBSTR 转换
22
23
24示例
25
26说明
27此示例演示如何从 CComBSTR 转换为上面列出的其他字符串类型。
28
29// convert_from_ccombstr.cpp// compile with /clr /link comsuppw.lib
30#include <iostream>#include <stdlib.h>#include <string>
31#include "atlbase.h"#include "atlstr.h"#include "comutil.h"#include "vcclr.h"
32using namespace std;using namespace System;using namespace System::Runtime::InteropServices;
33  int main(){ CComBSTR orig("Hello, World!"); CW2A printstr(orig); cout << printstr << " (CComBSTR)" << endl;
34 // Convert to a char* const size_t newsize = 100; char nstring[newsize]; CW2A tmpstr1(orig); strcpy_s(nstring, tmpstr1); strcat_s(nstring, " (char *)"); cout << nstring << endl;
35 // Convert to a wchar_t* wchar_t wcstring[newsize]; wcscpy_s(wcstring, orig); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl;
36 // Convert to a _bstr_t_bstr_t bstrt(orig); bstrt += " (_bstr_t)"; cout << bstrt << endl;
37 // Convert to a CString CString cstring(orig); cstring += " (CString)"; cout << cstring << endl;
38 // Convert to a basic_string wstring basicstring(orig); basicstring += L" (basic_string)"; wcout << basicstring << endl;
39 // Convert to a System::String String ^systemstring = gcnew String(orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 输出
40Hello, World! (CComBSTR)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CString)Hello, World! (basic_string)Hello, World! (System::String)
41从 CString 转换
42
43
44示例
45
46说明
47此示例演示如何从 CString 转换为上面列出的其他字符串类型。
48
49// convert_from_cstring.cpp// compile with /clr /link comsuppw.lib
50#include <iostream>#include <stdlib.h>#include <string>
51#include "atlbase.h"#include "atlstr.h"#include "comutil.h"
52using namespace std;using namespace System;
53int main(){ CString orig("Hello, World!"); wcout << orig << " (CString)" << endl;
54 // Convert to a char* const size_t newsize = 100; char nstring[newsize]; strcpy_s(nstring, orig); strcat_s(nstring, " (char *)"); cout << nstring << endl;
55 // Convert to a wchar_t* // You must first convert to a char * for this to work. size_t origsize = strlen(orig) + 1; size_t convertedChars = 0; wchar_t wcstring[newsize]; mbstowcs_s(&convertedChars, wcstring, origsize, orig, _TRUNCATE); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl;
56 // Convert to a _bstr_t _bstr_t bstrt(orig); bstrt += " (_bstr_t)"; cout << bstrt << endl;
57 // Convert to a CComBSTR CComBSTR ccombstr(orig); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; }
58 // Convert to a basic_string string basicstring(orig); basicstring += " (basic_string)"; cout << basicstring << endl;
59 // Convert to a System::String String ^systemstring = gcnew String(orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 输出
60Hello, World! (CString)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (basic_string)Hello, World! (System::String)
61从 basic_string 转换
62
63
64示例
65
66说明
67此示例演示如何从 basic_string 转换为上面列出的其他字符串类型。
68
69// convert_from_basic_string.cpp// compile with /clr /link comsuppw.lib
70#include <iostream>#include <stdlib.h>#include <string>
71#include "atlbase.h"#include "atlstr.h"#include "comutil.h"
72using namespace std;using namespace System;
73int main(){ string orig("Hello, World!"); cout << orig << " (basic_string)" << endl;
74 // Convert to a char* const size_t newsize = 100; char nstring[newsize]; strcpy_s(nstring, orig.c_str()); strcat_s(nstring, " (char *)"); cout << nstring << endl;
75 // Convert to a wchar_t* // You must first convert to a char * for this to work. size_t origsize = strlen(orig.c_str()) + 1; size_t convertedChars = 0; wchar_t wcstring[newsize]; mbstowcs_s(&convertedChars, wcstring, origsize, orig.c_str(), _TRUNCATE); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl;
76 // Convert to a _bstr_t _bstr_t bstrt(orig.c_str()); bstrt += " (_bstr_t)"; cout << bstrt << endl;
77 // Convert to a CComBSTR CComBSTR ccombstr(orig.c_str()); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; }
78 // Convert to a CString CString cstring(orig.c_str()); cstring += " (CString)"; cout << cstring << endl;
79 // Convert to a System::String String ^systemstring = gcnew String(orig.c_str()); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;}输出
80
81
82
83
84Hello, World! (basic_string)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (System::String)
85从 System::String 转换
86
87
88示例
89
90说明
91此示例演示如何从 System.String 转换为上面列出的其他字符串类型。
92
93// convert_from_system_string.cpp// compile with /clr /link comsuppw.lib
94#include <iostream>#include <stdlib.h>#include <string>
95#include "atlbase.h"#include "atlstr.h"#include "comutil.h"#include "vcclr.h"
96using namespace std;using namespace System;using namespace System::Runtime::InteropServices;
97int main(){ String ^orig = gcnew String("Hello, World!"); Console::WriteLine("{0} (System::String)", orig);
98 pin_ptr<const wchar_t> wch = PtrToStringChars(orig);
99 // Convert to a char* size_t origsize = wcslen(wch) + 1; const size_t newsize = 100; size_t convertedChars = 0; char nstring[newsize]; wcstombs_s(&convertedChars, nstring, origsize, wch, _TRUNCATE); strcat_s(nstring, " (char *)"); cout << nstring << endl;
100 // Convert to a wchar_t* wchar_t wcstring[newsize]; wcscpy_s(wcstring, wch); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl;
101 // Convert to a _bstr_t _bstr_t bstrt(wch); bstrt += " (_bstr_t)"; cout << bstrt << endl;
102// Convert to a CComBSTR
103 CComBSTR ccombstr(wch); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; }
104 // Convert to a CString CString cstring(wch); cstring += " (CString)"; cout << cstring << endl;
105 // Convert to a basic_string wstring basicstring(wch); basicstring += L" (basic_string)"; wcout << basicstring << endl;
106 delete orig;} 输出
107Hello, World! (System::String)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (basic_string)
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