Peer Instruction: Exception Multiple Choice Questions

Q-1: Select the correct type for each variable

a = 7 + 3
b = 3.1415
c = 7 < 3

• int, int, int
• Try again. A float is a number with a fractional part and a boolean is a true or false value of an expression.
• int, float, boolean
• Correct! 3 + 4 evaluates to 7, which is a whole number. 3.1415 has a fracional part, and 7 < 3 is the false value of an expression.
• int, float, int
• Try again. 7 < 3 here represents the false value of an expression.
• float, real, boolean
• Try again. 3 + 4 evaluates to 7, which is a whole number, and 3.1415 has a fracional part.
• I don’t know
• Try again. 3 + 4 evaluates to 7, which is a whole number. 3.1415 has a fracional part, and 7 < 3 is the false value of an expression.

Q-2: What type will this print?

def add(x, y):
    z = x + y
    return z
print(type(add(5,1)))

• int
• Correct! add(5,1) outputs 6, which is a whole number. And type() returns class type of the object.
• function
• Try again. add(5,1) = 5 + 1 = 6. And type() returns class type of the object.
• real
• Try again. add(5,1) = 5 + 1 = 6. And type() returns class type of the object.
• This will cause an error
• Try again. add(5,1) generates a new number. And type() returns class type of the object while print() prints the result out.
• I don’t know
• Try again. add(5,1) = 5 + 1 = 6. And type() returns class type of the object while print() prints the result out.

Q-3: Which code will print the value of i, i times?

A.
i = 5
print(i*i)

B.
i = 5
print(str(i)*str(i))

C.
i = 5
print(str(i)*i)

• Try again. i*i multiplies i with i rather than output value.
• Try again. str(i) is a string type and it cannot get multiplied by another string.
• Correct! str(i)*i will multiply i in the string type for i times.
• None of the above
• Try again. str(i) can change i into a string type. Multiply str(i) and i will have the value of i for i times.
• I don't know
• Try again. str(i) can change i into a string type. Multiply str(i) and i will have the value of i for i times.

Q-4: What does the following code print?

try:
          x = 1/0
          print("Math is lame!")
except Exception as e:
          print("Algebraic!")

• "Math is lame"
• Try again. Because x = 1/0 causes an error. Once the error appears, it will be detected by Exceptions. And the program will jump to Exception execution.
• "Algebraic!"
• Correct! Because x=1/10 causes an error which is detected by Exceptions.
• Nothing, this will cause an error
• Try again. Yes, this will cause an error. But the error will be detected by Exceptions. So the program will not stop.
• I don’t know
• Try again. Because x = 1/0 can cause an error. Once the error appears, it will be detected by Exceptions. And the program will jump to Exception execution.

Q-5: Which of the following rewrites this code using Elif?

grade = 98
if grade > = 90:
    print('You got an A!)
if grade > = 80 and grade < 90:
    print('You got a B!')
if grade < 80:
    print ('You got something else')

A.

    grade = 98
    if (grade >= 90):
        print('You got an A!')
    elif (grade < 90):
            print('You got a B!')
    elif (grade >= 80):
            print('You got a B!')
    elif (grade < 80):
            print ('You got something else')


B.

    grade = 98
    if (grade >= 90):
            print('You got an A!')
    elif (grade >= 80):
            print('You got a B!')
    else:
            print ('You got something else')


C.

    grade = 98
    elif (grade >= 90):
            print('You got an A!')
    elif (grade >= 80):
            print('You got a B!')
    elif (grade < 80):
            print ('You got something else')


D.

    grade = 98
    if (grade >= 90):
            print('You got an A!')
    elif (grade >= 80) and (grade < 90):
            print('You got a B!')
    else:
            print ('You got something else')

• Try again. You can get a right result if grade is 98. But if there is any grade under 90, the result will always be 'You got a B!' since the second condition can always be satisfied.
• Correct! If the condition for if is False , it checks the condition of the next elif block and so on. If previous condition is satisfied, the body of elif will not be executed.
• Try again. This will cause a syntax error because there is no If leading the whole block.
• Try again. You can get a right result but grade < 90 in elif (grade >= 80) and (grade < 90) is redundant because elif block will be executed only if if block is not satisfied.
• I don't know
• Try again. There are three different conditions and output: grade > 90 --> 'You got an A!'; 80 <= grade < 90 --> 'You got a B!'; grade < 80 --> 'You got something else'. Considering to use the 'if...elif...else' structure to distinguish these conditions.

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