Question

In fib(6) after how many function calls 7th addition will be taken place?

Comments

then you are correct ...

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@srestha and @Vijay sir what is fib(6) here and how did you solve it ?

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himanich 

here fib(n) = fib(n-1) + fib(n-2)

and fib(1)= 1 , fib(2)= 1,

or  fib(0)= 0, fib(1) = 1.

now run this recursion for fib(6) and keep counting '+' operator .. and stop when 7th '+' operator comes. 

Answer 1

Recurrence Relation for Fib

T(n) = $\left\{\begin{matrix} 0 & if n=0 or 1 & \\ T(n-1) +t(n-2) + 1&if n>1 & \end{matrix}\right.$

Following this reccurence relation make a fib(6) ternary tree ( like T(2) goes to T(1) T(0) and +)

Now Function Calling - Pre-order
        Function Execution - post order
So there will be 16 function call before 7th addition.