C language implements window jitter

#include ""
#include <>
#include<>
int main()
{

  int shake_time = 50; //The sleep time is 5 milliseconds  int shake_distance = 10; //Move 10 pixels  RECT rect; //RECT is a rectangular structure, which is equivalent to saving the coordinates of four sides of a rectangle  HWND window = NULL, oldwindow = NULL; //Two window handles  int x, y, width, height; //Variables used to save window horizontal and vertical coordinates, width and height  int i;
  //Thumb 50 times  for (i = 0; i < 10; i++) {
    window = GetForegroundWindow(); //Get the activity window    if (window != oldwindow) {
      //Get the location of the specified window      GetWindowRect(window, &rect);
      x = ;
      y = ;
      width =  - x;
      height =  - y;
      oldwindow = window;
    }
    MoveWindow(window, x - shake_distance, y, width, height, TRUE); //Move the window, move 10 pixels to the left, the same below    Sleep(shake_time); //Sleep time milliseconds, thread sleeps    MoveWindow(window, x - shake_distance, y - shake_distance, width, height, TRUE);
    Sleep(shake_time);
    MoveWindow(window, x, y - shake_distance, width, height, TRUE);
    Sleep(shake_time);
    MoveWindow(window, x, y, width, height, TRUE);
    Sleep(shake_time);
  }
  return 0;
}