In-Class Questions and Video Solutions

Lecture 7

  1. Black Box and Glass Box Testing

    With the below implementation, is the test set “n = 4 | n = -4 | n = 5” path complete?

    def is_even(n):
        """ 
        Returns True if a number is even
        and False if not 
        """
        if n > 0 and n % 2 == 0:
            return True
        elif n < 0 and n % 2 == 0:
            return True
        else: 
            return False
    

    With the above implementation, which value for n is incorrectly labeled by is_even?

  2. Errors

    Below is a piece of code and an error shown when running it. What is the problem?

    L = 3
    for i in range(len(L)):
        print(i)
    
    ERROR MESSAGE:
    
     File "C:/Users/Ana/.spyder2-py3/temp.py", line 2, in 
        for i in range(len(L)):
    
    TypeError: object of type 'int' has no len()
    

  3. Exceptions

    If the user enters “twenty” in the code below what does the program do?

    try:
        n = int(input("How old are you? "))
        percent = round(n*100/80, 1)
        print("You've gone through", percent, "% of your life!")
    except ValueError:
        print("Oops, must enter a number.")
    except ZeroDivisionError:
        print("Division by zero.")
    except:
        print("Something went very wrong.")
    

    If the user enters “0” in the code above what does the program do?

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