khungwindow

//ve khung chieu dai b - a. rong 3 hang.
void KhungChuNhat(int a, int b)
 {
	int i;
	for (i = a; i <= b; i++)
	{
		gotoxy(i, 17); 		printf("\xcd");
		gotoxy(i, 19); 		printf("\xcd");
	}
	gotoxy(a, 17);
	printf("\xc9");
	gotoxy(a, 18); 		printf("\xba");
	gotoxy(a, 19); 		printf("\xc8");
	gotoxy(b, 17); 		printf("\xbb");
	gotoxy(b, 18); 		printf("\xba");
	gotoxy(b, 19); 		printf("\xbc");
}