Question : C# Ref Parameter Question? How to call a method that has Ref parameter recursively?

Hello,

I am trying to compute fibonacci number recursively and calling computeFibonacciRecursive(ref fib); from main.
However, I am getting error from
return computeFibonacciRecursive(ref n - 1) + computeFibonacciRecursive(ref n - 2);
The error is:

A ref or out argument must be an assignable variable

How to fix this error? Please help.

class Program{
static void Main(string[] args){
int fib = 20;
computeFibonacci(ref fib);Console.WriteLine(fib);
fib = 20;
computeFibonacciRecursive(ref fib);Console.WriteLine(fib);
}

private static int computeFibonacciRecursive(ref int n)
{
if (n <= 1)
{
return n;
}
else
{
return computeFibonacciRecursive(ref n - 1) + computeFibonacciRecursive(ref n - 2); //<------
}
}

private static int computeFibonacci(ref int n)
{
int a = 1, b = 1;
for (int i = 3; i <= n; i++)
{
int c = a + b;
a = b;
b = c;
Console.WriteLine("b is= " + b);
}
return b;
}

}

Answer : C# Ref Parameter Question? How to call a method that has Ref parameter recursively?

you don't need the 'ref' because you already returning a value...

                       
         
           
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             class Program
    {
        static void Main(string[] args)
        {
            int fib = 20;
            fib = computeFibonacci(fib); Console.WriteLine(fib);
            fib = 20;
            fib = computeFibonacciRecursive(fib); Console.WriteLine(fib);
        }

        private static int computeFibonacciRecursive(int n)
        {
            if (n <= 1)
            {
                return n;
            }
            else
            {
                return computeFibonacciRecursive(n - 1) + computeFibonacciRecursive(n - 2);  //<------
            }
        }

        private static int computeFibonacci(int n)
        {
            int a = 1, b = 1;
            for (int i = 3; i <= n; i++)
            {
                int c = a + b;
                a = b;
                b = c;
                Console.WriteLine("b is= " + b);
            }
            return b;
        }

    }

           
         