[C#]using System.Runtime.InteropServices;[StructLayout(LayoutKind.Sequential)]public struct Point {public int x;public int y;} [StructLayout(LayoutKind.Explicit)]public struct Rect {[FieldOffset(0)] public int left;[FieldOffset(4)] public int top;[FieldOffset(8)] public int right;[FieldOffset(12)] public int bottom;} class Win32API {[DllImport("User32.dll")]public static extern bool PtInRect(ref Rect r, Point p);}