國立暨南國際大學 102 學年度第一學期小考試卷

1. (10%) Determine whether the following code is correct or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   # Defining how to print out an object
   
   class Rational:
       def __init__(self, n, d):
           self.numerator = n
           self.denominator = d
       def __str__(self):
           return str(self.numerator) + '/' + str(self.denominator)
   
   def main():
       a = Rational(6, 8)
       print(a)
   
   main()
   
   
   
2. (10%) Determine whether the following code is correct or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   # Reduce a rational number automatically reduces before it is printed out
   
   def gcd(a, b):      # Greatest Common Divisor
       if b == 0:
           return a
       else:
           return gcd(b, a % b)
   
   class Rational:
       def __init__(self, n, d):
           self.numerator = n
           self.denominator = d
       def reduce(self):
           g = gcd(self.numerator, self.denominator)
           self.numerator = self.numerator // g
           self.denominator = self.denominator // g
       def __str__(self):
           self.reduce()
           return str(self.numerator) + '/' + str(self.denominator)
   
   def main():
       a = Rational(6, 8)
       print(a)
   
   main()
   
   
   
   
3. (10%) Determine whether the following code is correct or not.  If it is correct, predict its output.  If it is incorrect, point out the mistake(s).
   
   # Modify a list within a function
   
   def update(lst):
       lst = lst + [5]
       lst[0] = 3
   
   def main():
       a = [2]
       update(a)
       print(a)
   
   main()