C / C++ / MFC

RECT	rectParent, rectDialog;
SIZE	sizeParent, sizeDialog;
POINT	point;

// get the size of the dialog
GetWindowRect(hDialog, &rectDialog);
sizeDialog.cx = rectDialog.right - rectDialog.left;
sizeDialog.cy = rectDialog.bottom - rectDialog.top;

// get the size of the parent Window's client area
GetClientRect(GetParent(hDialog), &rectParent);
sizeParent.cx = rectParent.right - rectParent.left;
sizeParent.cy = rectParent.bottom - rectParent.top;

// parent's sizes minus dialog's sizes divided by 2
// give the coordinates of the centre position
point.x = (sizeParent.cx - sizeDialog.cx) / 2;
point.y = (sizeParent.cy - sizeDialog.cy) / 2;
// we need to make parent coordinates relative to the screen
ClientToScreen(GetParent(hDialog), &point);

// now move the Window to the new position
MoveWindow(hDialog, point.x, point.y, sizeDialog.cx, sizeDialog.cy, true);

Quote:

y task is to make a function to append int to char*, using C style and end up with char*

1. Passing a buffer containing the source string, but also large enought to contain the target one.
2. Pass only the source string, and return a freshly allocated buffer containing the target one. Then it is caller task to eventually release the memory.

#define MAX_BUFFER 100
char * CLASS_LCM1602::BuildMessage(char *title, int value)
{
    // allocate a new buffer for the return message
    char* buffer = (char*)malloc(MAX_BUFFER );
    snprintf(buffer, MAX_BUFFER , "%s %d", title, value); // this assumes 100 characters is enough
    
    return buffer;
}

char *message = i2c.BuildMessage(title, value);
printf("%s\n", message);
free(message); // release the buffer when finished with

Quote:

snprintf(buffer, sizeof(buffer), "%s %d", title, value); // this assumes 100 characters is enough

snprintf(buffer, 100, "%s %d", title, value); // this assumes 100 characters is enough

char * CLASS_LCM1602::BuildMessage(char *title, int value)
{
    // Get the length of the source string plus a space and space for the integer value
    // 2147483647 is the maximum value for an integer, so add a sign to get the max length
    // add 1 at the end for the trailing null character
    int bufferSize = strlen(title) + 1 + strlen("-2147483647") + 1; // actual maximum space required
    // allocate a new buffer for the return message
    char* buffer = (char*)malloc(bufferSize);
    snprintf(buffer, bufferSize, "%s %d", title, value); // this assumes 100 characters is enough
    
    return buffer;
}

CLASS_LCM1602 myCLASS_LCM1602 = .. some initialization;

/* now use your function */
std::cout << myCLASS_LCM1602.BuildMessage("Demo my Title", 10) << "\n";

int CLASS_LCM1602::BuildMessage(const char *title, int value, char* buffer, int bufSize)

char tempBuf[256];

BuildMessage(const char* pTitle, int value, char* pDstBuffer, size_t dstBufferLen);

snprintf

1. Have an event queue (practically - a single element) that contains pairs - <player, time="" of="" move="">
2. When a player makes a move, insert a <player, time="" of="" move=""> pair into the queue
3. Have a timer thread that updates the clock display every <tbd> milliseconds
4. Before updating the clock, it:
   4.1 Reads the current time using the same clock used by the player threads
   4.2 Checks the event queue to see if a move was made, and when it was made
   4.3 If a move was made, it updates the players' times, stops one clock, and starts the other