- Python Test 7 - Recursion

1. Which is the most appropriate definition for recursion?

A function execution instance that calls another execution instance of the same function

A function that calls itself

A class method that calls another class method

An in-built method that is automatically called

Only problems that are recursively defined can be solved using recursion.

False

True

Which of these is false about recursion?

Recursive functions run faster than non-recursive function

Recursion makes programs easier to understand

Recursive functions usually take more memory space than non-recursive function

Recursive function can be replaced by a non-recursive function

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 _____________________

fact(num)*fact(num-1)

num*(num-1)

(num-1)*(num-2)

num*fact(num-1)

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))

13

17

7

Infinite loop

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="")

110

011

3

Infinite loop

What is tail recursion?

A function where the recursive functions leads to an infinite loop

A recursive function that has two base cases

A function where the recursive call is the last thing executed by the function View Answer

A recursive function where the function doesn’t return anything and just prints the values

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:
 return tot
 else:
 return b(n-2, tot-2)

Both a() and b() are tail recursive

Both a() and b() aren’t tail recursive

a() is tail recursive but b() isn’t

b() is tail recursive but a() isn’t

Which of the following statements is false about recursion?

Every recursive function must have a return value

A recursive function makes the code easier to understand

Infinite recursion can occur if the base case isn’t properly mentioned

Every recursive function must have a base case

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))

50

100

74

Infinite loop

Recursion and iteration are the same programming approach.

True

False

What happens if the base condition isn’t defined in recursive programs?

Program runs n number of times where n is the argument given to the function

An exception is thrown

Program runs once

Program gets into an infinite loop

Which of these is not true about recursion?

Sequence generation is easier than a nested iteration

A complex task can be broken into sub-problems

Recursive calls take up less memory

Making the code look clean

Which of these is not true about recursion?

Recursive functions are easy to debug

The logic behind recursion may be hard to follow

Programs using recursion take longer time than their non-recursive equivalent

Recursive calls take up a lot of memory

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=" ")

0 1 1 2 3

0 1 1 2

0 1 2 3

An exception is thrown