CODEWITHSUNDEEP
c++windowsstringpointerscopy
Basj
Basj

Reputation: 46363

Create a new string from an old one

I'm using C++ (Windows environment). I have a : 

LPCWSTR mystring;

This works :

mystring = TEXT("Hello");

But how to do this ? :

mystring = ((((create a new string with text = the content which is in another LPCWSTR 'myoldstring'))))

Thanks a lot in advance!

PS : 

mystring = myoldstring;

would work , but it would not create a new string, it would be the same pointer. I want to create a new string !

Upvotes: 0

Views: 870

Answers (3)

user93353
user93353

Reputation: 14049

LPTSTR mystring;
mystring = new TCHAR[_tcslen(oldstring) + 1];
_tcscpy(mystring, oldstring);

... After you are done ...

delete [] mystring;

This is a complete program

#include <tchar.h>
#include <windows.h>
#include <string.h>

int main()
{
    LPCTSTR oldstring = _T("Hello");

    LPTSTR mystring;
    mystring = new TCHAR[_tcslen(oldstring) + 1];
    _tcscpy(mystring, oldstring);

    // Stuff

    delete [] mystring;


}

It compiles fine with cl /DUNICODE /D_UNICODE a.cpp

I used tchar macros. If you don't want to use it, then

#include <windows.h>
#include <string.h>

int main()
{
    LPCWSTR oldstring = L"Hello";

    LPWSTR mystring;
    mystring = new WCHAR[wcslen(oldstring) + 1];
    wcscpy(mystring, oldstring);

    // Stuff

    delete [] mystring;


}

Compiles fine with cl a.cpp

Upvotes: 2

Jerry Coffin
Jerry Coffin

Reputation: 490663

To use C++ standard strings, you need to include the <string> header. Since you're dealing with LPCWSTR (emphasis on the W part of that) you're dealing with wide characters, so you want to use wide strings (i.e., std::wstring instead of std::string).

#include <string>
#include <iostream>
#include <windows.h>

int main() { 
    LPCWSTR x=L"This is a string";

    std::wstring y = x;
    std::wcout << y;
}

Upvotes: 2

cowboydan
cowboydan

Reputation: 1102

what about

string myNewString = std::string(myOldString);

Just using the copy constructor of the string library.

Upvotes: 0

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