This code comes from a C++ book I'm currently reading, and it should show a menu....but it doesn't
The .EXE file that is on the cd accompanied with the book uses this code, and it works fine...what is wrong???
Code:
// PROG6_2.CPP - basic menus
// INCLUDES ///////////////////////////////////////////////
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <windowsx.h>
#include <winuser.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include "mymenu.h"
// DEFINES ////////////////////////////////////////////////
// defines for windows
#define WINDOW_CLASS_NAME "WINCLASS1"
#define WINDOW_WIDTH 320
#define WINDOW_HEIGHT 200
// GLOBALS ////////////////////////////////////////////////
HWND main_window_handle = NULL; // save the window handle
char buffer[80]; // used to print text
// FUNCTIONS //////////////////////////////////////////////
LRESULT CALLBACK WindowProc(HWND hwnd,
UINT msg,
WPARAM wparam,
LPARAM lparam)
{
// this is the main message handler of the system
PAINTSTRUCT ps; // used in WM_PAINT
HDC hdc; // handle to a device context
// what is the message
switch(msg)
{
case WM_CREATE:
{
// do initialization stuff here
return(0);
} break;
// process menu messages
case WM_COMMAND:
{
// get the dc
hdc = GetDC(hwnd);
// set the color
SetTextColor(hdc,RGB(0,0,255));
SetBkColor(hdc,RGB(0,0,0));
SetBkMode(hdc,OPAQUE);
// what menu item?
switch(wparam)
{
case ID_MYMENU_FILE_OPEN:
{
// print message
TextOut(hdc,0,100,"File->Open ",strlen("File->Open "));
} break;
case ID_MYMENU_FILE_CLOSE:
{
// print message
TextOut(hdc,0,100,"File->Close ",strlen("File->Close "));
} break;
case ID_MYMENU_FILE_EXIT:
{
// terminate the application
PostMessage(hwnd,WM_DESTROY,0,0);
} break;
case ID_MYMENU_HELP_ABOUT:
{
// print message
TextOut(hdc,0,100,"Help->About ",strlen("Help->About "));
// put up a message box
MessageBox(hwnd,"Poor Man's About","About Menus",MB_OK);
} break;
default: break;
} // end switch
// release the dc
ReleaseDC(hwnd,hdc);
// inform windows we handled message
return(0);
} break;
case WM_PAINT:
{
// start painting
hdc = BeginPaint(hwnd,&ps);
// end painting
EndPaint(hwnd,&ps);
return(0);
} break;
case WM_DESTROY:
{
// kill the application
PostQuitMessage(0);
return(0);
} break;
default:break;
} // end switch
// process any messages that we didn't take care of
return (DefWindowProc(hwnd, msg, wparam, lparam));
} // end WinProc
// WINMAIN ////////////////////////////////////////////////
int WINAPI WinMain( HINSTANCE hinstance,
HINSTANCE hprevinstance,
LPSTR lpcmdline,
int ncmdshow)
{
WNDCLASS winclass; // this will hold the class we create
HWND hwnd; // generic window handle
MSG msg; // generic message
HDC hdc; // generic dc
PAINTSTRUCT ps; // generic paintstruct
// first fill in the window class stucture
winclass.style = CS_DBLCLKS | CS_OWNDC |
CS_HREDRAW | CS_VREDRAW;
winclass.lpfnWndProc = WindowProc;
winclass.cbClsExtra = 0;
winclass.cbWndExtra = 0;
winclass.hInstance = hinstance;
winclass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
winclass.hCursor = LoadCursor(NULL, IDC_ARROW);
winclass.hbrBackground = GetStockObject(BLACK_BRUSH);
winclass.lpszMenuName = NULL;
winclass.lpszClassName = WINDOW_CLASS_NAME;
// register the window class
if (!RegisterClass(&winclass))
return(0);
// create the window
if (!(hwnd = CreateWindow(WINDOW_CLASS_NAME, // class
"Basic Menus", // title
WS_OVERLAPPEDWINDOW | WS_VISIBLE,
0,0, // x,y
WINDOW_WIDTH, // width
WINDOW_HEIGHT, // height
NULL, // handle to parent
NULL, // handle to menu
hinstance,// instance
NULL))) // creation parms
return(0);
// save the window handle in a global
main_window_handle = hwnd;
// load the menu in and attach it (method 3)
SetMenu(hwnd,LoadMenu(hinstance, "MYMENU"));
// enter main event loop
while(1)
{
if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))
{
// test if this is a quit
if (msg.message == WM_QUIT)
break;
// translate any accelerator keys
TranslateMessage(&msg);
// send the message to the window proc
DispatchMessage(&msg);
} // end if
// main game processing goes here
} // end while
// return to Windows like this
return(msg.wParam);
} // end WinMain
///////////////////////////////////////////////////////////
Last edited by CyberCarsten; Mar 2nd, 2001 at 09:50 AM.
Ok after stratching my head for a few minutes I got it. You must have have made your project as a console app and not a Win32 app. Create a new empty, win32 app and import your cpp, rc, and h files. Then you have a problem with your background brush. I just made it NULL to test it, but it works, and your menu shows.
MSVS 6, .NET & .NET 2003 Pro
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Pointers are related to references, but the difference is that you can't mess around with references as much -- they're a lot safer. An example:
Code:
int func(int *ptr) {
return (*ptr += 5); // Increment the data pointed to by ptr
}
int reffunc(int &ptr) {
return ptr += 5;
}
int main() {
int x = 3;
func(&x);
reffunc(x);
}
I refuse to tie my hands behind my back and hear somebody say "Bend Over, Boy, Because You Have It Coming To You". -- Linus Torvalds
func requires a pointer to the variable, which it then has to dereference (turning a pointer into a reference). Unfortunately if this pointer is invalid then the program will fail.
reffunc requires a reference to the variable, which it can use straight off. It doesn't need to dereference it since it's already a reference. This way it is protected against bad input.
The difference between pointers and references is slightly hazy and I only really understood it after just playing around seeing what worked and what didn't.
I refuse to tie my hands behind my back and hear somebody say "Bend Over, Boy, Because You Have It Coming To You". -- Linus Torvalds
I don't know if you have looked at the code above.
It's driving me crazy!!! I have tried to compile it with BC4.5, Bc5.5 and Dev-C++ 4, but the menu just wont show up! I don't get any errors....
Do you know what's wrong????
// MYMENU.H - header with menu id's
// Notice the clean naming I used for the id's you
// can very quickly figure out the menu, sub menu, and item
#define ID_MYMENU_FILE_OPEN 1000
#define ID_MYMENU_FILE_CLOSE 1001
#define ID_MYMENU_FILE_EXIT 1002
#define ID_MYMENU_HELP_ABOUT 2000
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hmm
Addresses? References?
. What is the difference between the 2 functions? Thanx 