void fun ( int a, int *b );

int main ( void )
{
  int i = 1, j = 2;

  fun ( i, &j );

  return ( 0 );
}

void fun ( int a, int *b )
{
  if ( 0 == a )
  {
    *b = *b + a;
  }
  else
  {
    *b = *b - a;
  }

  return ( a + 1 );  //违背1
}