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How to convert char to integer

sodyum (6)
Hello everyone.. I have the following code and when I press the Go button I want to sum 2 numbers who person entered in 2 text boxes and show the answer with message box. How to do that?
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  #if defined(UNICODE) && !defined(_UNICODE)
    #define _UNICODE
#elif defined(_UNICODE) && !defined(UNICODE)
    #define UNICODE
#endif

#include <tchar.h>
#include <windows.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = ("TextEntry");
char textSaved1[20];
char textSaved2[20];
HWND TextBox1, TextBox2;

int WINAPI WinMain (HINSTANCE hThisInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR lpszArgument,
                     int nCmdShow)
{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default colour as the background of the window */
    wincl.hbrBackground = GetSysColorBrush(COLOR_3DFACE);

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           _T("ADDITION"),       /* Title Text */
           WS_SYSMENU | WS_MINIMIZEBOX, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           200,                 /* The programs width */
           100,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nCmdShow);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)                  /* handle the messages */
    {
        case WM_CREATE:

            TextBox1 = CreateWindow("EDIT",
                                    "",
                                    WS_BORDER | WS_CHILD | WS_VISIBLE,
                                    10, 10, 50, 20,
                                    hwnd, NULL, NULL, NULL);
            TextBox2 = CreateWindow("EDIT",
                                    "",
                                    WS_BORDER | WS_CHILD | WS_VISIBLE,
                                    10, 40, 50, 20,
                                    hwnd, NULL, NULL, NULL);
            CreateWindow("BUTTON",
                         "Go",
                         WS_VISIBLE | WS_CHILD | WS_BORDER,
                         130, 10 ,60 ,20,
                         hwnd, (HMENU) 1, NULL, NULL);

                break;
        case WM_COMMAND:

            switch (LOWORD(wParam))
            {
                case 1:

                    int firstNumber = 0;
                    int secondNumber = 0;
                    char *t = &textSaved1[0];
                    char *y = &textSaved2[0];
                    firstNumber = GetWindowText(TextBox1, t, 20);
                    secondNumber = GetWindowText(TextBox2, y, 20);

                    ::MessageBox(hwnd, textSaved2, textSaved1, MB_OK);
                    break;
            }


                break;
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}
integralfx (897)
1
2
 
firstNumber = GetWindowText(TextBox1, t, 20);
secondNumber = GetWindowText(TextBox2, y, 20);

How do you know that the user will enter 20 characters?

To get the number from a character do this
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char c{ '7' };
int n{ c - '0' };
std::cout << n << "\n";		// 7
sodyum (6)
I do not know what they mean, just found this code on the internet.. How can I use your code in my program? Can you help me?
Thomas1965 (4571)
One way to do it:
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#if defined(UNICODE) && !defined(_UNICODE)
#define _UNICODE
#elif defined(_UNICODE) && !defined(UNICODE)
#define UNICODE
#endif

#include <tchar.h>
#include <windows.h>
#include <stdio.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = ("TextEntry");
char textSaved1[20];
char textSaved2[20];
HWND TextBox1, TextBox2;

int WINAPI WinMain (HINSTANCE hThisInstance,
  HINSTANCE hPrevInstance,
  LPSTR lpszArgument,
  int nCmdShow)
{
  HWND hwnd;               /* This is the handle for our window */
  MSG messages;            /* Here messages to the application are saved */
  WNDCLASSEX wincl;        /* Data structure for the windowclass */

  /* The Window structure */
  wincl.hInstance = hThisInstance;
  wincl.lpszClassName = szClassName;
  wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
  wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
  wincl.cbSize = sizeof (WNDCLASSEX);

  /* Use default icon and mouse-pointer */
  wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
  wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
  wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
  wincl.lpszMenuName = NULL;                 /* No menu */
  wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
  wincl.cbWndExtra = 0;                      /* structure or the window instance */
  /* Use Windows's default colour as the background of the window */
  wincl.hbrBackground = GetSysColorBrush(COLOR_3DFACE);

  /* Register the window class, and if it fails quit the program */
  if (!RegisterClassEx (&wincl))
    return 0;

  /* The class is registered, let's create the program*/
  hwnd = CreateWindowEx (
    0,                   /* Extended possibilites for variation */
    szClassName,         /* Classname */
    _T("ADDITION"),       /* Title Text */
    WS_SYSMENU | WS_MINIMIZEBOX, /* default window */
    CW_USEDEFAULT,       /* Windows decides the position */
    CW_USEDEFAULT,       /* where the window ends up on the screen */
    300,                 /* The programs width */
    200,                 /* and height in pixels */
    HWND_DESKTOP,        /* The window is a child-window to desktop */
    NULL,                /* No menu */
    hThisInstance,       /* Program Instance handler */
    NULL                 /* No Window Creation data */
    );

  /* Make the window visible on the screen */
  ShowWindow (hwnd, nCmdShow);

  /* Run the message loop. It will run until GetMessage() returns 0 */
  while (GetMessage (&messages, NULL, 0, 0))
  {
    /* Translate virtual-key messages into character messages */
    TranslateMessage(&messages);
    /* Send message to WindowProcedure */
    DispatchMessage(&messages);
  }

  /* The program return-value is 0 - The value that PostQuitMessage() gave */
  return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
  switch (message)                  /* handle the messages */
  {
  case WM_CREATE:
    TextBox1 = CreateWindow("EDIT", "",  WS_BORDER | WS_CHILD | WS_VISIBLE,   10, 10, 100, 30,
      hwnd, NULL, NULL, NULL);
    TextBox2 = CreateWindow("EDIT", "", WS_BORDER | WS_CHILD | WS_VISIBLE, 10, 40, 100, 30,
      hwnd, NULL, NULL, NULL);
    CreateWindow("BUTTON", "Go", WS_VISIBLE | WS_CHILD | WS_BORDER, 200, 10 ,60 ,30,
      hwnd, (HMENU) 1, NULL, NULL);
    break;
  case WM_COMMAND:
    switch (LOWORD(wParam))
    {
    case 1:
      {
        int firstNumber = 0;
        int secondNumber = 0;
        TCHAR szNumber1[20] = {0}; 
        TCHAR szNumber2[20] = {0};
        GetWindowText(TextBox1, szNumber1, 20);
        GetWindowText(TextBox2, szNumber2, 20);
        firstNumber = _ttoi(szNumber1);
        secondNumber = _ttoi(szNumber2);
        int result = firstNumber + secondNumber;
        TCHAR szResult[20] = {0};
        _stprintf(szResult, _T("Result: %d"), result);
        ::MessageBox(hwnd, szResult, _T("Result"), MB_OK);
        break;
      }
    }
    break;
    case WM_DESTROY:
      PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
      break;
    default:                      /* for messages that we don't deal with */
      return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
  }
sodyum (6)
Thank you so much!!
Thomas1965 (4571)
You are welcome.
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