Data Structure Questions and Answers-Sum of n Natural Numbers using Recursion

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Data Structure Questions and Answers-Sum of n Natural Numbers using Recursion

Question 6 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Consider the following code:

#include<stdio.h> int recursive....sum(int n) { if(n == 0) return 0; return .....; } int main() { int n = 5; int ans = recursive....sum(n); printf("%d", ans); return 0; }

Which of the following lines is the recurrence relation for the above code?

A
(n - 1) +recursive....sum(n)
B
n + recursive....sum(n)
C
n + recursive....sum(n - 1)
D
(n - 1) + recursive....sum(n - 1)
Question 6 Explanation: 
The recurrence relation for the above code is: n + recursive....sum(n - 1).

Question 7 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Consider the following code:

#include<stdio.h> int recursive....sum(int n) { if(n == 0) return 0; return n + recursive....sum(n - 1); } int main() { int n = 5; int ans = recursive....sum(n); printf("%d", ans); return 0; }

Which of the following is the base case for the above recursive code?

A
if(n == 0)
B
return 0
C
return n + recursive....sum(n - 1)
D
none of the mentioned
Question 7 Explanation: 
"if(n == 0)" is the base case for the above recursive code.

Question 8 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What is the time complexity of the above recursive implementation used to find the sum of the first n natural numbers?
A
O(1)
B
O(n)
C
O(n2)
D
O(n3)
Question 8 Explanation: 
The time complexity of the above recursive implementation used to find the sum of first n natural numbers is O(n).

Question 9 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which of the following methods used to find the sum of first n natural numbers has the least time complexity?
A
Recursion
B
Iteration
C
Binomial coefficient
D
All of the mentioned
Question 9 Explanation: 
Recursion and iteration take O(n) time to find the sum of first n natural numbers while binomial coefficient takes O(1) time.

Question 10 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What is the output of the following code?

#include<stdio.h> int recursive....sum(int n) { if(n == 0) return 0; return n + recursive....sum(n - 1); } int main() { int n = 5; int ans = recursive....sum(n); printf("%d", ans); return 0; }
A
10
B
15
C
21
D
none of the mentioned
Question 10 Explanation: 
The above code prints the sum of first 5 natural numbers, which is 15.

There are 10 questions to complete.