C++ Jump to case label error while doing windows.h

Question

I was programming C++ and came across an error that said "Jump to case label" that i could not fix.I searched the internet and found no solution that worked. How do i fix this error?

#include<iostream>
#include<windows.h>
using namespace std;
LRESULT CALLBACK WindowProcessMessages(HWND hwnd, UINT msg, WPARAM param, LPARAM lparam);
INT WINAPI WinMain(HINSTANCE currentInstance, HINSTANCE previousInstance, PSTR cmdLine, INT cmdCount){
   const char *CLASS_NAME = "myWin32WindowClass";
   WNDCLASS wc{};
   wc.hInstance = currentInstance;
   wc.lpszClassName = CLASS_NAME;
   wc.hCursor = LoadCursor(nullptr, IDC_ARROW);
   wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
   wc.lpfnWndProc = WindowProcessMessages;
   RegisterClass(&wc);
   CreateWindow(CLASS_NAME, "Operating System", WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, nullptr, nullptr, nullptr, nullptr);
   MSG msg{};
   while(GetMessage(&msg, nullptr, 0, 0)){
    TranslateMessage(&msg);
    DispatchMessage(&msg);
   }
   return 0;
}
#define ID_BUTTON 1
#define ID_BUTTON2 2
#define TEXTBOX 3
#define FILE_MENU_NEW 4
#define FILE_MENU_OPEN 5
#define FILE_MENU_EXIT 6 //<-"Jump to case label" error is right here
static HWND hwndTextbox;
LRESULT CALLBACK WindowProcessMessages(HWND hwnd, UINT msg, WPARAM param, LPARAM lparam){
    switch(msg){
        case WM_CREATE:{
            CreateWindow(TEXT("STATIC"), TEXT("value"), WS_VISIBLE | WS_CHILD, 10, 10, 100, 25, hwnd, (HMENU) NULL, NULL, NULL);
            CreateWindow(TEXT("BUTTON"), TEXT("testButton"), WS_CHILD | WS_VISIBLE, 10, 30, 80, 20, hwnd, (HMENU) ID_BUTTON, NULL, NULL);
            CreateWindow(TEXT("EDIT"), TEXT("VALUE"), WS_VISIBLE | WS_CHILD | WS_BORDER, 10, 70, 200, 20, hwnd, (HMENU) NULL, NULL, NULL );
            CreateWindow(TEXT("BUTTON"), TEXT("Title change"), WS_CHILD | WS_VISIBLE, 10, 130, 80, 20, hwnd, (HMENU) ID_BUTTON2, NULL, NULL);
            hwndTextbox = CreateWindow(TEXT("EDIT"), TEXT("Change To What?"), WS_VISIBLE | WS_CHILD | WS_BORDER, 10, 100, 200, 20, hwnd, (HMENU) TEXTBOX, NULL, NULL );
            HMENU hMenubar = CreateMenu();
            HMENU hFile = CreateMenu();
            HMENU hOptions = CreateMenu();
            HMENU hSubmenu = CreateMenu();
            AppendMenu(hSubmenu, MF_POPUP, NULL, "SubMenu Item");
            AppendMenu(hMenubar, MF_POPUP, (UINT_PTR)hFile, "File");
            AppendMenu(hMenubar, MF_POPUP, NULL, "Edit");
            AppendMenu(hMenubar, MF_POPUP, (UINT_PTR)hOptions, "Options");
            AppendMenu(hFile, MF_STRING, FILE_MENU_EXIT, "Exit");
            AppendMenu(hFile, MF_POPUP, (UINT_PTR)hSubmenu, "Open Submenu");
            AppendMenu(hOptions, MF_STRING, NULL, "Option 1");
            AppendMenu(hOptions, MF_SEPARATOR, NULL, NULL);
            AppendMenu(hOptions, MF_STRING, NULL, "Option 2");
            SetMenu(hwnd, hMenubar);
            break;
        }
        case WM_COMMAND:{
            switch(LOWORD(param)){
                case ID_BUTTON:
                   MessageBox(hwnd, "button has been clicked", "title for popup", MB_ICONINFORMATION);
                   break;
                case ID_BUTTON2:
                    int len = GetWindowTextLength(hwndTextbox) + 1;
                    static char title[500];
                    GetWindowText(hwndTextbox, title, len);
                    SetWindowText(hwnd, title);
                case FILE_MENU_EXIT:
                    DestroyWindow(hwnd);
                    break;
                case
            }
            break;
        }
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
        default:
            return DefWindowProc(hwnd, msg, param, lparam);
    }
}

Answer 1

Here, you are creating variables that exist in the same scope as other cases, but whose initialization is skipped by those cases.

That's what the error is telling you.

case ID_BUTTON2:
    int len = GetWindowTextLength(hwndTextbox) + 1;
    static char title[500];
    GetWindowText(hwndTextbox, title, len);
    SetWindowText(hwnd, title);

You can fix it by limiting the scope of these variables.

case ID_BUTTON2:
{
    int len = GetWindowTextLength(hwndTextbox) + 1;
    static char title[500];
    GetWindowText(hwndTextbox, title, len);
    SetWindowText(hwnd, title);
}

You may have also overlooked a break; for that case.