Write a recursive C++ function that inputs a nonnegative integer n and returns the nth Fibonacci number

Write a C++ recursive function int fib(int n) that returns the value of the n’th Fibonaccinumber . Do not use a loop. Test it in the main program, not in the function.The Fibonacci sequence is0 1 1 2 3 5 8 13 21…Each Fibonacci number is the sum of the preceding two Fibonacci numbers.

Please IN C++ Write the simplest program that will demonstrate iteration vs recursion using the following guidelines -  Write two primary helper functions - one iterative (IsArrayPrimeIter) and one recursive (IsArrayPrimeRecur) - each of which Takes an array of integers and its size as input params and returns a bool such that 'true' ==> all elements of the array are prime, so the array is prime, 'false' ==> at least one element in array is not prime, so array is not prime.  Print out a message "Entering <function_name>" as the first executed statement of each function. Perform the code to test whether every element of the array is a Prime number. Print out a message "Leaving <function_name>" as the last executed statement before returning from the function. Remember - there will be nested loops for the iterative function and there can be no loops at all in the recursive function. For the recursive function - define one other helper function (IsPrimeRecur) which…

In C++ Consider the following recursive function (Chapter 17, #9, modified)   void recFun(int x) {       if (x > 10)       {            recFun(x / 10);            cout<< x % 10;       }       else            cout<< x; }   How can the code be modified so that the sum of all digits is printed?