Engineering Questions with Answers - Multiple Choice Questions

# Python MCQs

1 - Question

1. Which is the most appropriate definition for recursion?
a) A function that calls itself
b) A function execution instance that calls another execution instance of the same function
c) A class method that calls another class method
d) An in-built method that is automatically called

Explanation: The appropriate definition for a recursive function is a function execution instance that calls another execution instance of the same function either directly or indirectly.

2 - Question

2. Only problems that are recursively defined can be solved using recursion.
a) True
b) False

Explanation: There are many other problems can also be solved using recursion.

3 - Question

3. Which of these is false about recursion?
a) Recursive function can be replaced by a non-recursive function
b) Recursive functions usually take more memory space than non-recursive function
c) Recursive functions run faster than non-recursive function
d) Recursion makes programs easier to understand

Explanation: The speed of a program using recursion is slower than the speed of its non-recursive equivalent.

4 - Question

4. Fill in the line of the following Python code for calculating the factorial of a number.

```def fact(num):
if num == 0:
return 1
else:
return _____________________```

a) num*fact(num-1)
b) (num-1)*(num-2)
c) num*(num-1)
d) fact(num)*fact(num-1)

Explanation: Suppose n=5 then, 5*4*3*2*1 is returned which is the factorial of 5.

5 - Question

5. What will be the output of the following Python code?

```def test(i,j):
if(i==0):
return j
else:
return test(i-1,i+j)
print(test(4,7))```

a) 13
b) 7
c) Infinite loop
d) 17

Explanation: The test(i-1,i+j) part of the function keeps calling the function until the base condition of the function is satisfied.

6 - Question

6. What will be the output of the following Python code?

```l=[]
def convert(b):
if(b==0):
return l
dig=b%2
l.append(dig)
convert(b//2)
convert(6)
l.reverse()
for i in l:
print(i,end="")```

a) 011
b) 110
c) 3
d) Infinite loop

Explanation: The above code gives the binary equivalent of the number.

7 - Question

7. What is tail recursion?
a) A recursive function that has two base cases
b) A function where the recursive functions leads to an infinite loop
c) A recursive function where the function doesn’t return anything and just prints the values
d) A function where the recursive call is the last thing executed by the function

Explanation: A recursive function is tail recursive when recursive call is executed by the function in the last.

8 - Question

8. Observe the following Python code?

```def a(n):
if n == 0:
return 0
else:
return n*a(n - 1)
def b(n, tot):
if n == 0:
else:
return b(n-2, tot-2)```

a) Both a() and b() aren’t tail recursive
b) Both a() and b() are tail recursive
c) b() is tail recursive but a() isn’t
d) a() is tail recursive but b() isn’t

Explanation: A recursive function is tail recursive when recursive call is executed by the function in the last.

9 - Question

9. Which of the following statements is false about recursion?
a) Every recursive function must have a base case
b) Infinite recursion can occur if the base case isn’t properly mentioned
c) A recursive function makes the code easier to understand
d) Every recursive function must have a return value

Explanation: A recursive function needn’t have a return value.

10 - Question

10. What will be the output of the following Python code?

```def fun(n):
if (n > 100):
return n - 5
return fun(fun(n+11));

print(fun(45))```

a) 50
b) 100
c) 74
d) Infinite loop

Explanation: The fun(fun(n+11)) part of the code keeps executing until the value of n becomes greater than 100, after which n-5 is returned and printed.

11 - Question

11. Recursion and iteration are the same programming approach.
a) True
b) False

Explanation: In recursion, the function calls itself till the base condition is reached whereas iteration means repetition of process for example in for-loops.

12 - Question

12. What happens if the base condition isn’t defined in recursive programs?
a) Program gets into an infinite loop
b) Program runs once
c) Program runs n number of times where n is the argument given to the function
d) An exception is thrown

Explanation: The program will run until the system gets out of memory.

13 - Question

13. Which of these is not true about recursion?
a) Making the code look clean
b) A complex task can be broken into sub-problems
c) Recursive calls take up less memory
d) Sequence generation is easier than a nested iteration

Explanation: Recursive calls take up a lot of memory and time as memory is taken up each time the function is called.

14 - Question

14. Which of these is not true about recursion?
a) It’s easier to code some real-world problems using recursion than non-recursive equivalent
b) Recursive functions are easy to debug
c) Recursive calls take up a lot of memory
d) Programs using recursion take longer time than their non-recursive equivalent

Explanation: Recursive functions may be hard to debug as the logic behind recursion may be hard to follow.

15 - Question

15. What will be the output of the following Python code?

```def a(n):
if n == 0:
return 0
elif n == 1:
return 1
else:
return a(n-1)+a(n-2)
for i in range(0,4):
print(a(i),end=" ")```

a) 0 1 2 3
b) An exception is thrown
c) 0 1 1 2 3
d) 0 1 1 2