Why does sum hasn't been initialized to 0 during every time when it calling itself,by the way, what does static means in here?

Question

using System;
using System.Collections.Generic;

namespace SoloLearn
{
class Program
{
static int Counter(ref int x)
{
int sum = 0;
sum += x;
if (x == 1)
{
return sum;
}
else
{
x = x - 1;
return sum+Counter(ref x);

}
}
static void Main(string[] args)
{

int a = Convert.ToInt32(Console.ReadLine());
Console.WriteLine(Counter( ref a));
}

}

}

Answer 1

Yasswecancn

Program is working fine. What you expect here?

sum is initialise with 0 but you assigned again x to sum. So sum will have some value.

Answer 2

Yes,but shouldn't sum be ing initialized when I calling it at start of next
Loop/iteration?

Answer 3

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace SoloLearn
{
class Program
{
static void Main(string[] args)
{
int number = Convert.ToInt32(Console.ReadLine());

Console.WriteLine(Sum( ref number));
}

static int Sum( ref int num)
{

int sum = 0;

sum += num;
if (num == 0)
{
Console.WriteLine(sum);
return sum;
}
num--;
return sum + Sum( ref num);
//complete the recursive method

}
}
}

Answer 4

Here is a similar code I've been dealing with. It has the same algorithm, but I still didn't get it because how could sum in the WriteLine box is 0,and 1 line later it turns into 15 if you enter 5?