Fibonacci number
Given a non-negative integer, write a method that returns n-th element of Fibonacci sequence.
Expected input and output
FibonacciNumber(3) → 2
FibonacciNumber(7) → 13
using System;
namespace CSharpExercises.Exercises.Recursion
{
class FibonacciNumberTask
{
static int FibonacciNumber(int num)
{
return num <= 1 ? num : FibonacciNumber(num - 2) + FibonacciNumber(num - 1);
}
static void Main(string[] args)
{
Console.WriteLine(FibonacciNumber(10)); // 55
Console.WriteLine(FibonacciNumber(0)); // 0
Console.WriteLine(FibonacciNumber(20)); // 6765
Console.WriteLine(FibonacciNumber(13)); // 233
}
}
}