Mine

#include <windows.h>
#include <string>
using namespace std;
#include "KWnd.h";

enum UserMsg {UM_THREAD_DONE = WM_USER+1};
struct ThreadManager {
	ThreadManager (string _name) : name (_name) {nValue = 0;}
	HWND hwndParent;
	string name;
	int nValue;
};

ThreadManager tm_A (string ("A"));
ThreadManager tm_B (string ("B"));
ThreadManager tm_C (string ("C"));
DWORD WINAPI ThreadFuncA (LPVOID);
DWORD WINAPI ThreadFuncB (LPVOID);
DWORD WINAPI ThreadFuncC (LPVOID);

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

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
	setlocale (LC_ALL, ".1251");
	MSG msg;
	KWnd mainWnd (L" ", hInstance, nCmdShow, WndProc, NULL, 100, 100, 400, 160);
	while (GetMessage (&msg, NULL, 0, 0)) {
		TranslateMessage (&msg);
		DispatchMessage (&msg);
	}
	return (msg.wParam);
}

LRESULT CALLBACK WndProc (HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) {
	HDC hDC;
	PAINTSTRUCT ps;
	static HANDLE hThreadA, hThreadB, hThreadC;
	static char text [200];
	ThreadManager* pTm;
	static int y = 0;

	switch (uMsg) {
	case WM_CREATE:
		tm_A.hwndParent = hWnd;
		hThreadA = CreateThread (NULL, 0, ThreadFuncA, &tm_A, 0, NULL);
		if (!hThreadA)
			MessageBox (hWnd, L"not A", NULL, MB_OK);

		tm_B.hwndParent = hWnd;
		hThreadB = CreateThread (NULL, 0, ThreadFuncB, &tm_B, 0, NULL);
		if (!hThreadB)
			MessageBox (hWnd, L"not B", NULL, MB_OK);

		tm_C.hwndParent = hWnd;
		hThreadC = CreateThread (NULL, 0, ThreadFuncC, &tm_C, 0, NULL);
		if (!hThreadC)
			MessageBox (hWnd, L"not C", NULL, MB_OK);
		break;

	case UM_THREAD_DONE:
		pTm = (ThreadManager*) wParam;
		sprintf (text, "%s:count = %d", pTm->name.c_str(), pTm->nValue);
		y += 30;
		InvalidateRect (hWnd, NULL, FALSE);
		break;

	case WM_PAINT:
		hDC = BeginPaint (hWnd, &ps);
		TextOut (hDC, 20, y, LPCTSTR (text), strlen (text));
		EndPaint (hWnd, &ps);
		break;

	case WM_DESTROY:
		CloseHandle (hThreadA);
		CloseHandle (hThreadB);
		CloseHandle (hThreadC);
		PostQuitMessage (0);
		break;
	default:
		return DefWindowProc (hWnd, uMsg, wParam, lParam);
	}
	return 0;
}

DWORD WINAPI ThreadFuncA (LPVOID lpv) {
	ThreadManager* pTm = (ThreadManager*) lpv;
	int count = 0;
	for (int i=0; i<100000000; ++i) count++;
	pTm->nValue = count;
	SendMessage (pTm->hwndParent, UM_THREAD_DONE, (WPARAM)pTm, 0);
	return 0;
}

DWORD WINAPI ThreadFuncB (LPVOID lpv) {
	ThreadManager* pTm = (ThreadManager*) lpv;
	int count = 0;
	for (int i=0; i<50000000; ++i) count++;
	pTm->nValue = count;
	SendMessage (pTm->hwndParent, UM_THREAD_DONE, (WPARAM)pTm, 0);
	return 0;
}

DWORD WINAPI ThreadFuncC (LPVOID lpv) {
	ThreadManager* pTm = (ThreadManager*) lpv;
	int count = 0;
	for (int i=0; i<20000; ++i) count++;
	pTm->nValue = count;
	SendMessage (pTm->hwndParent, UM_THREAD_DONE, (WPARAM)pTm, 0);
	return 0;
}