Using GetWindowText

I'm trying to get a number from an edit box and just have it multiplyed but since GetWindowText uses a character buffer i can't multiply it and if i use something like atoi() when i go to pass it back to the SetWindowText it tells me that it can't convert char to int. So how would i get an intiger from an edit box(i'm not using a dialog) do some mathmatical equation on it and return it to the SetWindoText to display it back in the edit box again?

Here is a sample code.

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myEditBox.SetWindowText("2002");

// Now you want to multiply 2002 by 2

CString num;
myEditBox.GetWindowText(&num);
long temp = atol(&num) * 2;
num.Format("%d", temp);
myEditBox.SetWindowText(num);
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Kuphryn

I'm still getting the error Cannot convert 'int' to 'const char *' that was my original problem. I'm usinc borlands compliler 5.5 if that makes any difference.

Oh. You're using Borland. I am not sure about Borland C++.

Kuphryn

anyone else got any ideas how to make this work?

Code:

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




LRESULT CALLBACK WindowProc(HWND, UINT, WPARAM, LPARAM);

char szClassName[] = "WindowsApp";
HINSTANCE g_hInst;


int WINAPI WinMain(HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpszArgument, int nFunsterStil)

{
    HWND hwnd;             
        MSG messages;           
        WNDCLASSEX wincl;
       
        g_hInst = hThisInstance;

    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProc;     
    wincl.style = CS_DBLCLKS;             
    wincl.cbSize = sizeof(WNDCLASSEX);
    wincl.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor(NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;
    wincl.cbClsExtra = 0;
    wincl.cbWndExtra = 0;
        wincl.hbrBackground = (HBRUSH) GetStockObject(LTGRAY_BRUSH);

   
    if(!RegisterClassEx(&wincl)) return 0;

 
    hwnd = CreateWindowEx(0,szClassName, "Poor Man's Calc",
                WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,
                200,120, HWND_DESKTOP,NULL,           
          hThisInstance,NULL );   

 
    ShowWindow(hwnd, nFunsterStil);
        UpdateWindow(hwnd);
 
    while(GetMessage(&messages, NULL, 0, 0))
    {
          TranslateMessage(&messages);
          DispatchMessage(&messages);
    }

    return messages.wParam;
}


LRESULT CALLBACK WindowProc(HWND hwnd, UINT message,
                                                        WPARAM wParam, LPARAM lParam)
{
        static HWND hEdit,hButton;
        char str[10];
        int x;

    switch (message)               
    {
          case WM_CREATE:           
         
                          hEdit = CreateWindow("EDIT","",WS_CHILD | WS_VISIBLE,
                                  10,10,100,30,hwnd,NULL,g_hInst,NULL);

                          hButton = CreateWindow("BUTTON","Multiply by 10",
                                  WS_CHILD | WS_VISIBLE,10,50,100,30,hwnd,NULL,g_hInst,NULL);
          break;
         
          case WM_COMMAND:
                          if((HWND) lParam == hButton){
                                  GetWindowText(hEdit,str,10);
                                  if(str[0] == 0)
                                          break;
                                  x = atoi(str);
                                  if(x)
                                          SetWindowText(hEdit,itoa(x*10,str,10));
                                  else
                                          MessageBox(hwnd,"Error",NULL,NULL);
                          }
         
          break;
         
          case WM_DESTROY:
          PostQuitMessage(0);       
          break;
          default:                 
          return DefWindowProc(hwnd, message, wParam, lParam);
    }
    return 0;
}

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Use atoi and itoa....

You could use GetDlgItemInt()

Thanks, that worked.

i have one more probles, it works fine, you enter the number and it gets multiplyed but when i certain numbers though it returns a value thats not it multiplies like i could enter 6 and it will return the letter c. any one have a fix for this, also it doesn't read a number like 1.2 it only multiplys the 1 in 1.2

And is there a style or something that only allows numbers to be enter in an edit box?

use something like sprintf()

After you get the number from the edit (use ES_NUMBER for numerical input only, or isdigit() on string)

atoi() or atof(), make sure you cast correctly

then sprintf() back to text to set into the edit.

sprintf(sBuffer,"%02.2f",fNum);