# Data Structure Questions and Answers-Fibonacci using Recursion

## Data Structure Questions and Answers-Fibonacci using Recursion

 Question 6 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Consider the following recursive implementation to find the nth fibonacci number:

`int fibo(int n) { if(n == 1) return 0; else if(n == 2) return 1; return .....; } int main() { int n = 5; int ans = fibo(n); printf("%d", ans); return 0; }`

Which of the following lines should be inserted to complete the above code?

 A fibo(n - 1) B fibo(n - 1) + fibo(n - 2) C fibo(n) + fibo(n - 1) D fibo(n - 2) + fibo(n - 1)
Question 6 Explanation:
The line fibo(n - 1) + fibo(n - 2) should be inserted to complete the above code.

 Question 7 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Consider the following recursive implementation to find the nth fibonnaci number:

`int fibo(int n) { if(n == 1) return 0; else if(n == 2) return 1; return fibo(n - 1) + fibo(n - 2); } int main() { int n = 5; int ans = fibo(n); printf("%d", ans); return 0; }`

Which of the following is the base case?

 A if(n == 1) B else if(n == 2) C return fibo(n - 1) + fibo(n - 2) D both if(n == 1) and else if(n == 2)
Question 7 Explanation:
Both if(n == 1) and else if(n == 2) are the base cases.

 Question 8 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What is the time complexity of the above recursive implementation to find the nth fibonacci number?
 A O(1) B O(2*n) C O(n2) D O(2n)
Question 8 Explanation:
The time complexity of the above recursive implementation to find the nth fibonacci number is O(2n).

 Question 9 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What is the space complexity of the above recursive implementation to find the nth fibonacci number?
 A O(1) B O(2*n) C O(n2) D O(2n)
Question 9 Explanation:
The space complexity of the above recursive implementation to find the nth fibonacci number is O(1).

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

`int fibo(int n) { if(n == 1) return 0; else if(n == 2) return 1; return fibo(n - 1) + fibo(n - 2); } int main() { int n = -1; int ans = fibo(n); printf("%d", ans); return 0; }`
 A 0 B 1 C Compile time error D Runtime error
Question 10 Explanation:
Since negative numbers are not handled by the program, the function fibo() will be called infinite times and the program will produce a runtime error when the stack overflows.

There are 10 questions to complete.