Is there a better way to implement a word replacement feature in the Win32 API?

Question

I am creating a note pad application and I already have the basic stuff done (open file, save file, write to a file). I am now trying to add a word replacement feature just like the one in MS WORD which finds the inputted word and replaces all of its occurrences with the new word. Below is my code.

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

#define FILE_MENU_EXIT 2
#define FILE_MENU_BUILD 3
#define FILe_MENU_OPEN 4
#define FILE_MENU_SAVE 5
#define SEARCH_MENU_REPLACE 6

HMENU hMenu;
HMENU hDevMenu;
HWND hEdit,hCurrentPath;

HWND hOldWord,hNewWord;

int messagebox_id;

void replacerDialog(HINSTANCE);
void StillUnderConst();
void AddMenu(HWND);
void AddControls(HWND);
void AddDialogButton(HWND);



LRESULT CALLBACK WindowProcedure(HWND,UINT,WPARAM,LPARAM);
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrevInst , LPSTR args, int ncmdshow)
{
    WNDCLASSW wc = {0};

    wc.hbrBackground = (HBRUSH)COLOR_WINDOW;
    wc.hCursor = LoadCursor(NULL,IDC_ARROW);
    wc.hInstance = hInst;
    wc.lpszClassName = L"mywindowclass";
    wc.lpfnWndProc = WindowProcedure;
    if(!RegisterClassW(&wc))
        return -1;

    replacerDialog(hInst);
    CreateWindowW(L"mywindowclass",L"Note Book",WS_VISIBLE|WS_MINIMIZEBOX|WS_SYSMENU,50,50,1000,650,NULL,NULL,NULL,NULL);
    MSG msg = {0};

    while(GetMessage(&msg,NULL,NULL,NULL))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return 0;
}

void display_file(char* path)
{
    FILE *file;
    //this function helps us open and access the file passed in
    file = fopen(path,"rb");
    //this function helps as move to certain parts of the file thats why its a file pointer
    fseek(file,0,SEEK_END);
    //the ftell() function retuurn an integer type whic is stored in a var so that the file can later be read
    //it is a needed to have the file size to be able to read fromt the file thats why we went for its size
    int _size = ftell(file);
    //this takes us back to the beginning of he file
    rewind(file);
    //this is thevar in which the files data will be kept
    char *data = new char[_size+1];
    //the fread function helps us to read from of specified file
    //fread function requires us to know the file size to be able to read from it
    fread(data,_size,1,file);

    data[_size] ='\0';

    SetWindowText(hEdit,data);
    fclose(file);

}

void open_file(HWND hWnd)
{
    OPENFILENAME ofn;
    ZeroMemory(&ofn,sizeof(OPENFILENAME));

    char file_name[100];
    //the memory allocated to the the ofn struct
    ofn.lStructSize = (sizeof(OPENFILENAME));
    //the owner of the dialog
    ofn.hwndOwner = hWnd;
    //the path of the file being open
    ofn.lpstrFile = file_name;
    ofn.lpstrFile[0] = '\0';
    //the max length being allocated to the path
    ofn.nMaxFile = 100;
    ofn.lpstrFilter = "All file\0*.*\0Text files\0*.txt\0C++ files\0*.cpp\0";
    ofn.nFilterIndex = 1;

    //creates an openfile dialog based on the kind of structure passed in as an argument
    GetOpenFileName(&ofn);
    SetWindowText(hCurrentPath,ofn.lpstrFile);

  //  MessageBox(NULL,ofn.lpstrFile,NULL,MB_OK);

    display_file(ofn.lpstrFile);
}

void write_file(char* path)
{
    FILE *file;
    //this function helps us open and access the file passed in
    file = fopen(path,"w");


    int _size = GetWindowTextLength(hEdit);
    char *data = new char[_size+1];
    GetWindowText(hEdit,data,_size+1);

    fwrite(data,_size+1,1,file);
    fclose(file);
}
void save_file(HWND hWnd)
{
    OPENFILENAME ofn;
    ZeroMemory(&ofn,sizeof(OPENFILENAME));

    char file_name[100];
    //the memory allocated to the the ofn struct
    ofn.lStructSize = (sizeof(OPENFILENAME));
    //the owner of the dialog
    ofn.hwndOwner = hWnd;
    //the path of the file being open
    ofn.lpstrFile = file_name;
    ofn.lpstrFile[0] = '\0';
    //the max length being allocated to the path
    ofn.nMaxFile = 100;
    ofn.lpstrFilter = "All file\0*.*\0Text files\0*.txt\0C++ files\0*.cpp\0";
    ofn.nFilterIndex = 1;

    //creates an openfile dialog based on the kind of structure passed in as an argument
    GetSaveFileName(&ofn);

    write_file(ofn.lpstrFile);

}

LRESULT CALLBACK DialogProcedure(HWND hWnd,UINT msg,WPARAM wp,LPARAM lp)
{
    switch(msg)
    {
    case WM_CREATE:
        AddDialogButton(hWnd);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd,msg,wp,lp);
    }
    return 0;
}
void replacerDialog(HINSTANCE hInst)
{
    WNDCLASSW dialog = {0};

    dialog.hbrBackground = (HBRUSH)COLOR_WINDOW;
    dialog.hCursor = LoadCursor(NULL,IDC_ARROW);


    dialog.hInstance = hInst;
    dialog.lpszClassName = L"mywindowdialog";
    dialog.lpfnWndProc = DialogProcedure;
    RegisterClassW(&dialog);

}

void displayDialog(HWND hWnd)
{
    CreateWindowW(L"mywindowdialog",L"Replacer",WS_VISIBLE|WS_MINIMIZEBOX|WS_SYSMENU,50,50,300,300,hWnd,NULL,NULL,NULL);

}
void replacer(HWND hWnd)
{
    char oword[100];
    char nword[100];
    wchar_t data[100000];
    GetWindowText(hOldWord,oword,100);
    GetWindowText(hNewWord,nword,100);
    GetWindowText(hEdit,data,100000);

    size_t startpos = data.find(oword);
    data.replace(startpos,oword.length(),nword);



}

void AddDialogButton(HWND hWnd)
{
    CreateWindowW(L"Static",L"Please enter the old word:",WS_CHILD|WS_VISIBLE,2,2,250,25,hWnd,NULL,NULL,NULL);
    hOldWord = CreateWindowW(L"Edit",L"",WS_CHILD|WS_VISIBLE|WS_BORDER,10,20,250,30,hWnd,NULL,NULL,NULL);

    CreateWindowW(L"Static",L"Please enter the new word:",WS_CHILD|WS_VISIBLE,2,100,250,25,hWnd,NULL,NULL,NULL);
    hNewWord = CreateWindowW(L"Edit",L"",WS_CHILD|WS_VISIBLE|WS_BORDER,10,125,250,30,hWnd,NULL,NULL,NULL);

    CreateWindowW(L"Button",L"Replace",WS_VISIBLE|WS_CHILD,220,220,70,40,hWnd,NULL,NULL,NULL);
}
LRESULT CALLBACK WindowProcedure(HWND hWnd,UINT msg,WPARAM wp,LPARAM lp)
{
    switch(msg)
    {
    case WM_KEYDOWN:
        if (wp == VK_ESCAPE)
        {
            MessageBoxW(NULL,L"You just left clicked", NULL,MB_OK);
        }
    //The WM_COMMAND is sent to the windowproc when a button or menu is clicked
    case WM_COMMAND:
        //WPARAM is an argument that represents the IDs of menus and button
        switch(wp)
        {
        case SEARCH_MENU_REPLACE:
            displayDialog(hWnd);
            break;
        case FILE_MENU_SAVE:
            save_file(hWnd);
            break;
        case FILe_MENU_OPEN:
            open_file(hWnd);
            break;
        case FILE_MENU_EXIT:
            messagebox_id = MessageBoxW(NULL,L"Are you sure?",L"Attention",MB_YESNO|MB_ICONEXCLAMATION);
            if(messagebox_id == IDYES)
            {
                DestroyWindow(hWnd);
            }
            break;
        }
        break;
    //WM_CREATE function is called when evr the window is created ,this is to initiate all of the components such as buttons and menus
    case WM_CREATE:
        AddControls(hWnd);
        AddMenu(hWnd);
        break;
    case WM_DESTROY:

        PostQuitMessage(0);
        break;
    default:
        return DefWindowProcW(hWnd,msg,wp,lp);
    }

}

void AddMenu(HWND hWnd)
{
    hMenu = CreateMenu();
    HMENU hFileMEnu = CreateMenu();
    HMENU hSearchMenu =CreateMenu();

    AppendMenu(hMenu,MF_POPUP,(UINT_PTR)hFileMEnu,"FILE");
    AppendMenu(hMenu,MF_STRING,NULL,"EDIT");
    AppendMenu(hMenu,MF_STRING,NULL,"VIEW");
    AppendMenu(hMenu,MF_POPUP,(UINT_PTR)hSearchMenu,"SEARCH");
    AppendMenu(hMenu,MF_STRING,(UINT_PTR)FILE_MENU_BUILD,"BUILD");
    AppendMenu(hMenu,MF_STRING,NULL,"HELP");

    //sub menus under the file menu
    AppendMenu(hFileMEnu,MF_STRING,NULL,"NEW");
    AppendMenu(hFileMEnu,MF_STRING,(UINT_PTR)FILe_MENU_OPEN,"OPEN");
    AppendMenu(hFileMEnu,MF_STRING,(UINT_PTR)FILE_MENU_SAVE,"SAVE");
    AppendMenu(hFileMEnu,MF_STRING,FILE_MENU_EXIT,"EXIT");

    AppendMenu(hSearchMenu,MF_STRING,NULL,"FIND");
    AppendMenu(hSearchMenu,MF_STRING,(UINT_PTR)SEARCH_MENU_REPLACE,"REPLACE");
    AppendMenu(hSearchMenu,MF_STRING,NULL,"GO TO");



    //this is used to declare where and what menu is to cretaed
    //SetMenu(handler(usually window handler),what menu is being set);
    SetMenu(hWnd,hMenu);

}

void AddControls(HWND hWnd)
{
    hCurrentPath = CreateWindowW(L"Static",NULL,WS_CHILD|WS_VISIBLE|WS_BORDER,750,2,200,20,hWnd,NULL,NULL,NULL);
    hEdit = CreateWindowW(L"Edit",NULL,WS_CHILD|WS_VISIBLE|WS_BORDER|WS_VSCROLL|ES_MULTILINE,5,25,980,550,hWnd,NULL,NULL,NULL);

}

I tried using the find() function to find the starting position of the word to be replaced then used the replace() function to replace the old word with the new word but all am getting is errors. Below is the block for the replacer.

void replacer()
{
    char oword[100];
    char nword[100];
    wchar_t data[100000];
    GetWindowText(hOldWord,oword,100);
    GetWindowText(hNewWord,nword,100);
    GetWindowText(hEdit,data,100000);

    size_t startpos = data.find(oword);
    data.replace(startpos,oword.length(),nword);



}

Answer 1

I modified the code, and it runs well like this:

void replacer(HWND hWnd)
{

   
    char nword[100];
    std::string data;
    std::string oword;
    GetWindowText(hOldWord, (LPSTR)oword.c_str(), 100);
    GetWindowText(hNewWord, nword, 100);
    GetWindowText(hEdit, (LPSTR)data.c_str(), 100000);

    size_t startpos = data.find(oword);
    data.replace(startpos, oword.length(), nword);
}