How to: Convert Between Various string types

This topic demonstrates how to convert various visual c ++ string types into other strings. The strings types that are covered includeChar *,Wchar_t *, _ Bstr_t, ccombstr, cstring, basic_string,
And system. String. In all cases, a copy of the string is made when converted to the new type.
Any changes made to the new string will not affect the original string, and vice versa.

Converting from char * example

This example demonstrates how to convert fromChar *To the other string types listed abve.

// convert_from_char.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){    char *orig = "Hello, World!";    cout << orig << " (char *)" << endl;    // 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;    // Convert to a _bstr_t    _bstr_t bstrt(orig);    bstrt += " (_bstr_t)";    cout << bstrt << endl;    // Convert to a CComBSTR    CComBSTR ccombstr(orig);    if (ccombstr.Append(L" (CComBSTR)") == S_OK)    {        CW2A printstr(ccombstr);        cout << printstr << endl;    }    // Convert to a CString    CString cstring(orig);    cstring += " (CString)";    cout << cstring << endl;    // Convert to a basic_string    string basicstring(orig);    basicstring += " (basic_string)";    cout << basicstring << endl;    // Convert to a System::String    String ^systemstring = gcnew String(orig);    systemstring += " (System::String)";    Console::WriteLine("{0}", systemstring);    delete systemstring;}

Output

Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (basic_string)Hello, World! (System::String)

Converting from wchar_t * example

This example demonstrates how to convert fromWchar_t *To the other string types listed abve.

// convert_from_wchar_t.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){    wchar_t *orig = L"Hello, World!";    wcout << orig << L" (wchar_t *)" << endl;    // 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;    // Convert to a _bstr_t    _bstr_t bstrt(orig);    bstrt += " (_bstr_t)";    cout << bstrt << endl;    // Convert to a CComBSTR    CComBSTR ccombstr(orig);    if (ccombstr.Append(L" (CComBSTR)") == S_OK)    {        CW2A printstr(ccombstr);        cout << printstr << endl;    }    // Convert to a CString    CString cstring(orig);    cstring += " (CString)";    cout << cstring << endl;    // Convert to a basic_string    wstring basicstring(orig);    basicstring += L" (basic_string)";    wcout << basicstring << endl;    // Convert to a System::String    String ^systemstring = gcnew String(orig);    systemstring += " (System::String)";    Console::WriteLine("{0}", systemstring);    delete systemstring;}

Output

Hello, World! (wchar_t *)Hello, World! (char *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (basic_string)Hello, World! (System::String)

Converting from _ bstr_texample

This example demonstrates how to convert from_ Bstr_tTo the other string types listed abve.

// convert_from_bstr_t.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){    _bstr_t orig("Hello, World!");    wcout << orig << " (_bstr_t)" << endl;    // Convert to a char*    const size_t newsize = 100;    char nstring[newsize];    strcpy_s(nstring, (char *)orig);    strcat_s(nstring, " (char *)");    cout << nstring << endl;    // Convert to a wchar_t*    wchar_t wcstring[newsize];    wcscpy_s(wcstring, (wchar_t *)orig);    wcscat_s(wcstring, L" (wchar_t *)");    wcout << wcstring << endl;    // Convert to a CComBSTR    CComBSTR ccombstr((char *)orig);    if (ccombstr.Append(L" (CComBSTR)") == S_OK)    {        CW2A printstr(ccombstr);        cout << printstr << endl;    }    // Convert to a CString    CString cstring((char *)orig);    cstring += " (CString)";    cout << cstring << endl;    // Convert to a basic_string    string basicstring((char *)orig);    basicstring += " (basic_string)";    cout << basicstring << endl;    // Convert to a System::String    String ^systemstring = gcnew String((char *)orig);    systemstring += " (System::String)";    Console::WriteLine("{0}", systemstring);    delete systemstring;}

Output

Hello, World! (_bstr_t)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (basic_string)Hello, World! (System::String)

Converting from ccombstrexample

This example demonstrates how to convert fromCcombstrTo the other string types listed abve.

// convert_from_ccombstr.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"#include "vcclr.h"using namespace std;using namespace System;using namespace System::Runtime::InteropServices;int main(){    CComBSTR orig("Hello, World!");    CW2A printstr(orig);    cout << printstr << " (CComBSTR)" << endl;    // 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;    // Convert to a wchar_t*    wchar_t wcstring[newsize];    wcscpy_s(wcstring, orig);    wcscat_s(wcstring, L" (wchar_t *)");    wcout << wcstring << endl;    // Convert to a _bstr_t    _bstr_t bstrt(orig);    bstrt += " (_bstr_t)";    cout << bstrt << endl;    // Convert to a CString    CString cstring(orig);    cstring += " (CString)";    cout << cstring << endl;    // Convert to a basic_string    wstring basicstring(orig);    basicstring += L" (basic_string)";    wcout << basicstring << endl;    // Convert to a System::String    String ^systemstring = gcnew String(orig);    systemstring += " (System::String)";    Console::WriteLine("{0}", systemstring);    delete systemstring;}

Output

Hello, World! (CComBSTR)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CString)Hello, World! (basic_string)Hello, World! (System::String)

Converting from cstringexample

This example demonstrates how to convert fromCstringTo the other string types listed abve.

// convert_from_cstring.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){    CString orig("Hello, World!");    wcout << orig << " (CString)" << endl;    // Convert to a char*    const size_t newsize = 100;    char nstring[newsize];    strcpy_s(nstring, orig);    strcat_s(nstring, " (char *)");    cout << nstring << endl;    // 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;    // Convert to a _bstr_t    _bstr_t bstrt(orig);    bstrt += " (_bstr_t)";    cout << bstrt << endl;    // Convert to a CComBSTR    CComBSTR ccombstr(orig);    if (ccombstr.Append(L" (CComBSTR)") == S_OK)    {        CW2A printstr(ccombstr);        cout << printstr << endl;    }    // Convert to a basic_string    string basicstring(orig);    basicstring += " (basic_string)";    cout << basicstring << endl;    // Convert to a System::String    String ^systemstring = gcnew String(orig);    systemstring += " (System::String)";    Console::WriteLine("{0}", systemstring);    delete systemstring;}

Output

Hello, World! (CString)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (basic_string)Hello, World! (System::String)

Converting from basic_stringexample

This example demonstrates how to convert fromBasic_stringTo the other string types listed abve.

// convert_from_basic_string.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){    string orig("Hello, World!");    cout << orig << " (basic_string)" << endl;    // 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;    // 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;    // Convert to a _bstr_t    _bstr_t bstrt(orig.c_str());    bstrt += " (_bstr_t)";    cout << bstrt << endl;    // Convert to a CComBSTR    CComBSTR ccombstr(orig.c_str());    if (ccombstr.Append(L" (CComBSTR)") == S_OK)    {        CW2A printstr(ccombstr);        cout << printstr << endl;    }    // Convert to a CString    CString cstring(orig.c_str());    cstring += " (CString)";    cout << cstring << endl;    // Convert to a System::String    String ^systemstring = gcnew String(orig.c_str());    systemstring += " (System::String)";    Console::WriteLine("{0}", systemstring);    delete systemstring;}

Output

Hello, World! (basic_string)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (System::String)

Converting from system: stringexample

This example demonstrates how to convert fromSystem. StringTo the other string types listed abve.

// convert_from_system_string.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"#include "vcclr.h"using namespace std;using namespace System;using namespace System::Runtime::InteropServices;int main(){    String ^orig = gcnew String("Hello, World!");    Console::WriteLine("{0} (System::String)", orig);    pin_ptr<const wchar_t> wch = PtrToStringChars(orig);    // 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;    // Convert to a wchar_t*    wchar_t wcstring[newsize];    wcscpy_s(wcstring, wch);    wcscat_s(wcstring, L" (wchar_t *)");    wcout << wcstring << endl;    // Convert to a _bstr_t    _bstr_t bstrt(wch);    bstrt += " (_bstr_t)";    cout << bstrt << endl;    // Convert to a CComBSTR    CComBSTR ccombstr(wch);    if (ccombstr.Append(L" (CComBSTR)") == S_OK)    {        CW2A printstr(ccombstr);        cout << printstr << endl;    }    // Convert to a CString    CString cstring(wch);    cstring += " (CString)";    cout << cstring << endl;    // Convert to a basic_string    wstring basicstring(wch);    basicstring += L" (basic_string)";    wcout << basicstring << endl;    delete orig;}

Output

Hello, World! (System::String)Hello, World! (char *)Hello, World! (wchar_t *)Hello, World! (_bstr_t)Hello, World! (CComBSTR)Hello, World! (CString)Hello, World! (basic_string)