c++ build errors on win32 school application

Question

I haven't been programming in c++ very long, but need to make an Win32 application for my school. The teacher helped me a lot with information but after a few days of trying I am still stuck.

Errors:

error C2440: '=' : cannot convert from 'const char [11]' to 'LPCWSTR'
error C2664: 'CreateWindowExW' : cannot convert parameter 2 from 'const char [11]' to 'LPCWSTR'
error C2664: 'TextOutW' : cannot convert parameter 4 from 'char *' to 'LPCWSTR'
IntelliSense: argument of type "char *" is incompatible with parameter of type "LPCWSTR"

Don't know if all the other suff is right, but i only get those 4 error now

cpp file:

    /* Hoofdstuk 10, User Interface */
#include "Callback_NYCM.h"

// UI
int WINAPI WinMain(HINSTANCE thisInstance,HINSTANCE prevInstance,LPSTR lpCmdLine,int nShowCmd) 
{ 
    PAINTSTRUCT ps;
    HDC hdc;
    MSG msg;
    HWND hwnd;
    WNDCLASSEX wndclassex; //struct_WNDCLASSEX via windows.h    

    // toekenning
    wndclassex.cbSize = sizeof(WNDCLASSEX); 
    wndclassex.style = CS_HREDRAW | CS_VREDRAW;
    wndclassex.lpfnWndProc = WndProc;
    wndclassex.cbClsExtra = 0;
    wndclassex.cbWndExtra = 0;
    wndclassex.hInstance = thisInstance;
    wndclassex.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wndclassex.hCursor = LoadCursor(thisInstance,IDC_ARROW);  
    wndclassex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    wndclassex.lpszMenuName = NULL;  
    wndclassex.lpszClassName = "WNDCLASSEX"; 
    wndclassex.hIconSm = LoadIcon(NULL, IDI_APPLICATION); 

    // functie aanroep
    RegisterClassEx(&wndclassex);

// IfThen -> CreateWindows
    if(!(hwnd = CreateWindowEx(NULL,"WNDCLASSEX","Hoofdstuk 10",WS_OVERLAPPEDWINDOW 
        | WS_VISIBLE,50,50,650,300,NULL,NULL,thisInstance,NULL)))  
    {  
        return 0; 
    } 
// logische structuur
while(GetMessage(&msg, NULL, 0, 0))  
{  
    if(msg.message == WM_QUIT)    
        break;   
    TranslateMessage(&msg);   
    DispatchMessage(&msg);  
}  
return (int) msg.wParam; 
};

header file:

 /*Hoofdstuk 10, Deelnemer.h*/ 
//Declaratie 
class Deelnemer 
{ 
private: 
    char* nm; 
public: 

//Constructor 
Deelnemer(){
}
    //Methoden = prototype 
    void Deelnemer::Invoeren();
    char* Deelnemer::WeergevenNaam();
};  
//Implemenmtatie.Invoeren 
void Deelnemer::Invoeren() 
{
    nm = "Roy"; 
}  
//.Weergeven 
char* Deelnemer::WeergevenNaam()
{ 
    return nm;
}

callback_NYCM.h:

    /*Hoofdstuk 10, Callback_NYCM*/
#include "Windows.h"
#include "Deelnemer.h"  

// prototype
LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wparam,LPARAM lparam); 

//Implementatie 
LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wparam,LPARAM lparam) 
{  
    //Constructie  
    PAINTSTRUCT ps;
    HDC hdc;
    MSG msg;
    WNDCLASSEX wndclassex;
    // HWND hwnd;
    Deelnemer deelnemer1; 


    //UI   
    switch(message)
    {
    case WM_PAINT:    
        {     
            //Functieaanroep.Initialisatie     
            deelnemer1.Invoeren();          
            //.TextOut  
            TextOut(hdc,50,50,deelnemer1.WeergevenNaam(),     
            strlen(deelnemer1.WeergevenNaam()));     
            EndPaint(hwnd,&ps);     
            return 0;   
        }    
        break;
        case WM_DESTROY:    
            {     
                PostQuitMessage(0);     
                return 0;    
            }    
            break;   
        default:    
            {     
                return DefWindowProc(hwnd,message,wparam,lparam);    
            }    
            break; 
    }
    return 0;
}

I think my constructor or something like that is wrong and my return value for char* Deelnemer::WeergevenNaam()

Could somebody explain me what is wrong in my code so I know how to get it working?

UPDATE:

Updating your application requires to use UNICODE string literals throughout, i.e. L"MyString" instead of "MyString". You also need to use WCHAR/wchar_t in place of char

But how do i do this with my code, could somebody help?

UPDATE 2:

That solved al lot of errors!

But i have some more errors left in this part

Deelnemer deelnemer1;   
    switch(message)
    {
    case WM_PAINT:    
        {     
            //Functieaanroep.Initialisatie     
            deelnemer1.Invoeren();          
            //.TextOut  
        TextOut(hdc,50,50,deelnemer1.WeergevenNaam(),     
            strlen(deelnemer1.WeergevenNaam()));     
            EndPaint(hwnd,&ps);     
            return 0;   
        }

so the errors are on line: deelnemer1.WeergevenNaam()

-TextOutW' : cannot convert parameter 4 from 'char *' to 'LPCWSTR'

-IntelliSense: argument of type "char *" is incompatible with parameter of type "LPCWSTR"

UPDATE 3:

After some testing i found a solution (like you guys said below) But now i only got this one left: TextOut (hdc,50,50,deelnemer1.WeergevenNaam(), // on the deelnemer1.weergevenNaam()
with error C2664: 'TextOutW' : cannot convert parameter 4 from 'const char *' to 'LPCWSTR'

Answer 1

By choosing "not set" on Character Set in Project > Property > Configuration Properties > General, I was able to remove errors C2440 and C2264.

Answer 2

I have it working. The use wchar_t * and L"string". The problem with my code was more the structure because copy/pasting to a new project solved my errors. Thanks guys!

Answer 3

LPCWSTR -> Long Pointer to Constant Wide Character String.

All of your error messages reduce to some form of char[XX] is not the same type as wchar_t[XX].

Microsoft's Win32 API's are designed to compile either with ANSI strings, char, or wide character strings, wchar_t. This is why many Win32 function have two signatures, one ending in A, the other in W.

Example:

CreateWindowExW
CreateWindowExA

CreateWindowEx - A macro that expands to one of the above signatures depending on your build configuration. If you define UNICODE or _UNICODE it will expand to the W version.

Typically you use the macros when you are programming in Win32, and wrap all of your string literals with the _T macro. When defining character arrays that are strings, you'll want to use LPCTSTR and LPTSTR. These are also macros which will expand to either char * or wchar_t * depending on your build settings.

Answer 4

Your code is written to compile as ANSI but your solution settings include _UNICODE/UNICODE. You can either set your solution to use ANSI encoding by changing Character Set (on the General node of the Configuration Properties) from Use Unicode Character Set to Use Multi-Byte Character Set or update your application code (the latter is recommended).

Updating your application requires to use UNICODE string literals throughout, i.e. L"MyString" instead of "MyString". You also need to use WCHAR/wchar_t in place of char (where applicable) and call the wide versions of the Windows API. For many API calls there exists a wide version that has a W at the end, e.g. CreateWindowExW. If you are using the Standard C++ Library you will also want to make sure to use the UNICODE variants where character encoding is necessary (e.g. std::wstring instead of std::string). Additional information can be found at Text and Strings in Visual C++.

A bit more background about what is going on here: The Windows API and Microsoft's CRT implementation can be used to compile code using ANSI/Multi-Byte character set or UNICODE character set. To support both character encodings the C/C++ preprocessor replaces the respective character types and API calls with the specific implementations depending on whether or not the _UNICODE and UNICODE preprocessor symbol is defined.

For example, the call CreateWindowEx is expanded to either CreateWindowExA or CreateWindowExW. Both implementations have different parameter types for string arguments (char* and wchar_t* respectively). To use ANSI/Multi-Byte encoding the call would be CreateWindowExA(NULL,"WNDCLASSEX",...). For UNICODE it would look like CreateWindowExW(NULL,L"WNDCLASSEX",...).

To see what the code looks like after the preprocessor is through you can use the /P or /E compiler switches (assuming you're using the Microsoft Compiler).

Note: Don't forget to read The Absolute Minimum Every Software Developer Absolutely, Positively Must Know About Unicode and Character Sets (No Excuses!).

Answer 5

simple answer - with no explanation of why

change quoted strings to L"foo"

change char to wchar_t