function value = sphere_shell_volume_nd ( n, r1, r2 )

%*****************************************************************************80
%
%% sphere_shell_volume_nd() computes the volume of a spherical shell in ND.
%
%  Integration region:
%
%    Points X(1:N) such that:
%
%      R1**2 <= Sum ( X(1:N) - XC(1:N) )**2 <= R2**2.
%
%  Licensing:
%
%    This code is distributed under the MIT license. 
%
%  Modified:
%
%    20 May 2004
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    integer N, the dimension of the space.
%
%    real R1, R2, the radiuses of the inner and outer spheres.
%
%  Output:
%
%    real VALUE, the volume of the spherical shell.
%
  value = ball_volume_nd ( n, r2 ) - ball_volume_nd ( n, r1 );

  return
end
