编写一个程序，在屏幕中出现一个圆心沿正弦曲线轨迹移动的小圆，要求每隔四分之一周期，圆的填充色和圆的周边颜色都发生变化（颜色自己选取），同时，圆的半径在四分之一周期之内由正弦曲线幅值的0.2倍至0.6倍线性增长。小圆能从左向右再从右向左不间断移动。用c语言的windows库

以下是一个可能的实现：

#include <windows.h>
#include <math.h>

#define PI 3.14159265358979323846

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    WNDCLASS wc = {0};
    wc.lpfnWndProc = WndProc;
    wc.hInstance = hInstance;
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wc.lpszClassName = TEXT("MyWindowClass");
    RegisterClass(&wc);

    HWND hWnd = CreateWindow(TEXT("MyWindowClass"), TEXT("Moving Circle"), WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 640, 480, NULL, NULL, hInstance, NULL);

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);

    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return (int)msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    static int cxClient, cyClient;
    static int cxCenter, cyCenter;
    static int cxRadius, cyRadius;
    static int cxOffset, cyOffset;
    static COLORREF fillColor, borderColor;
    static double t = 0.0;

    switch (message)
    {
    case WM_CREATE:
        fillColor = RGB(255, 0, 0);
        borderColor = RGB(0, 255, 0);
        cxRadius = cyRadius = (int)(0.2 * cyClient);
        cxOffset = cyOffset = 0;
        SetTimer(hWnd, 1, 20, NULL);
        break;

    case WM_SIZE:
        cxClient = LOWORD(lParam);
        cyClient = HIWORD(lParam);
        cxCenter = cxClient / 2;
        cyCenter = cyClient / 2;
        break;

    case WM_TIMER:
        t += 0.05;
        if (t > 2 * PI)
            t -= 2 * PI;
        cxRadius = (int)(0.2 * cyClient + 0.4 * cyClient * (1 + sin(t)));
        if (cxOffset < cxClient)
            cxOffset += 2;
        else
            cxOffset = -cxRadius;
        InvalidateRect(hWnd, NULL, TRUE);
        break;

    case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);

            HBRUSH hFillBrush = CreateSolidBrush(fillColor);
            HBRUSH hOldBrush = (HBRUSH)SelectObject(hdc, hFillBrush);
            HPEN hBorderPen = CreatePen(PS_SOLID, 2, borderColor);
            HPEN hOldPen = (HPEN)SelectObject(hdc, hBorderPen);

            Ellipse(hdc, cxCenter - cxRadius + cxOffset, cyCenter - cyRadius + cyOffset,
                cxCenter + cxRadius + cxOffset, cyCenter + cyRadius + cyOffset);

            SelectObject(hdc, hOldBrush);
            DeleteObject(hFillBrush);
            SelectObject(hdc, hOldPen);
            DeleteObject(hBorderPen);

            EndPaint(hWnd, &ps);
        }
        break;

    case WM_DESTROY:
        KillTimer(hWnd, 1);
        PostQuitMessage(0);
        break;

    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }

    return 0;
}

这个程序使用了 Windows 库，创建了一个窗口，并在窗口中绘制了一个圆，圆心沿正弦曲线轨迹移动，同时圆的填充色和周边颜色每隔四分之一周期发生变化，圆的半径在四分之一周期内由正弦曲线幅值的0.2倍至0.6倍线性增长。程序使用了定时器来控制圆的移动和变化。