title: Divisibility By 7
signature: function divisibility_by_7(num)
test_code: using Printf
  
  # SOLUTION CODE
  # ============================================
  PLACEHOLDER_CODE_BODY
  
  # TESTING CODE 
  # ============================================
  function validate_solution(actual, expected)
      return actual == expected
  end
  
  function driver(num, expected)
      try
  
          if validate_solution(PLACEHOLDER_FN_NAME(num), expected)
              return "PASSED";
          end
          return "FAILED";
      catch exception_obj
          return string(Base.typename(typeof(exception_obj)).wrapper);
      end
  end
  
  function main()
      
      result = driver(0, true);
      @printf("TEST-0...%s\n",result);
      
      result = driver(-21, false);
      @printf("TEST-1...%s\n",result);
      
      result = driver(7, true);
      @printf("TEST-2...%s\n",result);
      
      result = driver(63, false);
      @printf("TEST-3...%s\n",result);
      
      result = driver(84, false);
      @printf("TEST-4...%s\n",result);
      
      result = driver(73, false);
      @printf("TEST-5...%s\n",result);
      
      result = driver(81, false);
      @printf("TEST-6...%s\n",result);
      
      result = driver(-10, false);
      @printf("TEST-7...%s\n",result);
      
      result = driver(47, false);
      @printf("TEST-8...%s\n",result);
      
      result = driver(23, false);
      @printf("TEST-9...%s\n",result);
      
  end
  
  main()
source_py: def divisibility_by_7(num):
      if (num < 0):
          return divisibility_by_7((- num))
      if ((num == 0) or (num == 7)):
          return True
      if (num < 10):
          return False
      return divisibility_by_7(((num / 10) - (2 * (num - ((num / 10) * 10)))))
source_cpp: int divisibility_by_7(int num) {
    if ( num < 0 ) return divisibility_by_7 ( - num );
    if ( num == 0 || num == 7 ) return 1;
    if ( num < 10 ) return 0;
    return divisibility_by_7 ( num / 10 - 2 * ( num - num / 10 * 10 ) );
  }