#include <windows.h>
 
#include <vector>
 
using std::vector;
 
 
 
LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
 
HINSTANCE g_hInst;
 
LPCTSTR lpszClass=TEXT("Mouse");
 
 
 
#pragma comment( linker , "/subsystem:windows")
 
int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance
 
                     ,LPSTR lpszCmdParam,int nCmdShow)
 
{
 
    HWND hWnd;
 
    MSG Message;
 
    WNDCLASS WndClass;
 
    g_hInst=hInstance;
 
    WndClass.cbClsExtra=0;
 
    WndClass.cbWndExtra=0;
 
    WndClass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
 
    WndClass.hCursor=LoadCursor(NULL,IDC_ARROW);
 
    WndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
 
    WndClass.hInstance=hInstance;
 
    WndClass.lpfnWndProc=WndProc;
 
    WndClass.lpszClassName=lpszClass;
 
    WndClass.lpszMenuName=NULL;
 
    WndClass.style=CS_HREDRAW | CS_VREDRAW;
 
    RegisterClass(&WndClass);
 
    hWnd=CreateWindow(lpszClass,lpszClass,WS_OVERLAPPEDWINDOW,
 
        CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,
 
        NULL,(HMENU)NULL,hInstance,NULL);
 
    ShowWindow(hWnd,nCmdShow);
 
    while (GetMessage(&Message,NULL,0,0)){
 
        TranslateMessage(&Message);
 
        DispatchMessage(&Message);
 
    }
 
    return (int)Message.wParam;
 
}
 
 
 
LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM lParam)
 
{
 
    HDC hdc;
 
    static int x;
 
    static int y;
 
    static vector<POINT>  ptlist;
 
    static vector< vector<POINT> >  lineList;
 
    PAINTSTRUCT ps;
 
    POINT pt;
 
 
 
    switch (iMessage)
 
    {
 
    case WM_LBUTTONDOWN:
 
        x=LOWORD(lParam);
 
        y=HIWORD(lParam);
 
        ptlist.clear();
 
        pt.x = x;
 
        pt.y = y;
 
        ptlist.push_back(pt);
 
        return 0;
 
 
 
    case WM_LBUTTONUP   : 
 
        lineList.push_back( ptlist);
 
        return 0;
 
 
 
    case WM_MOUSEMOVE:
 
        if((wParam & MK_LBUTTON))
 
        {
 
            hdc=GetDC(hWnd);
 
            MoveToEx(hdc,x,y,NULL);
 
            x=LOWORD(lParam);
 
            y=HIWORD(lParam);
 
            LineTo(hdc,x,y);
 
            ReleaseDC(hWnd,hdc);
 
            pt.x = x;
 
            pt.y = y;
 
            ptlist.push_back(pt);
 
        }
 
        return 0;
 
 
 
    case WM_PAINT   : 
 
        {
 
            hdc = BeginPaint(hWnd , &ps);
 
            for(size_t i =0 ; i < lineList.size() ; i++)
 
            {
 
                for(size_t j = 1 ; j < lineList[i].size() ; j++)
 
                {
 
                    MoveToEx(hdc, lineList[i][j-1].x ,lineList[i][j-1].y ,NULL);
 
                    LineTo(hdc,lineList[i][j].x ,lineList[i][j].y);
 
                }
 
            }
 
            EndPaint(hWnd , &ps);
 
        }
 
        return 0;
 
    case WM_DESTROY:
 
        PostQuitMessage(0);
 
        return 0;
 
    }
 
    return(DefWindowProc(hWnd,iMessage,wParam,lParam));
 
}

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