#! /usr/bin/env python
#
def dvec_sub ( n, dvec1, dvec2 ):

#*****************************************************************************80
#
## DVEC_SUB subtracts two decimal vectors.
#
#  Discussion:
#
#    A DVEC is an integer vector of decimal digits, intended to
#    represent an integer.  DVEC(1) is the units digit, DVEC(N-1)
#    is the coefficient of 10**(N-2), and DVEC(N) contains sign
#    information.  It is 0 if the number is positive, and 1 if
#    the number is negative.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    29 May 2015
#
#  Author:
#
#    John Burkardt
#
#  Parameters:
#
#    Input, integer N, the length of the vectors.
#
#    Input, integer DVEC1(N), DVEC2(N), the vectors to be subtracted.
#
#    Output, integer DVEC3(N), the value of DVEC1 - DVEC2.
#
  from dvec_add import dvec_add
  from dvec_complementx import dvec_complementx

  dvec4 = dvec_complementx ( n, dvec2 )

  dvec3 = dvec_add ( n, dvec1, dvec4 )

  return dvec3

def dvec_sub_test ( ):

#*****************************************************************************80
#
## DVEC_SUB_TEST tests DVEC_SUB;
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    29 May 2015
#
#  Author:
#
#    John Burkardt
#
  import platform
  from dvec_to_i4 import dvec_to_i4
  from i4_to_dvec import i4_to_dvec
  from i4_uniform_ab import i4_uniform_ab

  n = 10
  seed = 123456789
  test_num = 10

  print ( '' )
  print ( 'DVEC_SUB_TEST' )
  print ( '  Python version: %s' % ( platform.python_version ( ) ) )
  print ( '  DVEC_SUB subtracts decimal vectors representing integers;' )
  print ( '' )
  print ( '        I        J        L = I - J' )

  for test in range ( 0, test_num ):
    
    i, seed = i4_uniform_ab ( -100, 100, seed )
    j, seed = i4_uniform_ab ( -100, 100, seed )

    print ( '' )
    print ( '  %8d  %8d' % ( i, j ) )

    l = i - j

    print ( '  Directly:           %8d' % ( l ) )

    dvec1 = i4_to_dvec ( i, n )
    dvec2 = i4_to_dvec ( j, n )

    dvec4 = dvec_sub ( n, dvec1, dvec2 )
    l = dvec_to_i4 ( n, dvec4 )

    print ( '  DVEC_SUB  %8d' % ( l ) )
#
#  Terminate.
#
  print ( '' )
  print ( 'DVEC_SUB_TEST' )
  print ( '  Normal end of execution.' )
  return

if ( __name__ == '__main__' ):
  from timestamp import timestamp
  timestamp ( )
  dvec_sub_test ( )
  timestamp ( )