I am trying to code these functions in C recursively. But I do not know how to do it properly and am stuck. Please help. The question asks to also provide a prototype, definition and test in the main function.

2. Function fun2 (n) is defined as follows: 2 i=1 3. Fibonacci(n) - Fibonacci(n-1) Fibonacci(n-2); Where n is a positive integer n = 0 and Fibonacci(1) - 1; Fibonacci(0) = 0; 4. The gretest common divisor gcd(x,y) where gcd(x, y) -x, if y-0 otherwise gcd(x, y) = gcd(y, x MOD y), if y > 0