I need help with recursive sum

Question

I don't know how to do it, I tried it but I get an error. This is the description of the problem:

Write a program that takes N numbers as input and recursively calculates the sum of all numbers from 1 to N.

Input example
5

Output example
fifteen

Explanation
5 + 4 + 3 + 2 + 1 = 15.

This is code:

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(number));
}

static int Sum(int num)
{
//completa el método recursivo

}
}
}

Answer 1

recursive function must call itself until a base case...

if you give N as argument, you must return N+Sum(N-1) until N reach 0...

so:

if (num == 0) {
return 0;
}
return num + Sum(num - 1);

Answer 2

Okay, now I understand it better. I really appreciate your help, it helped me a lot, I understood it better and I learned something new. Thank you visph

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(number));
}

static int Sum(int num)
{
//complete the recursive method
so:

if (num == 0) {
return 0;
}
return num + Sum(num - 1);
}
}
}

Answer 4

show us your try wich give error, so we could help you to correct it ;)

Answer 5

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(number));
}

static int Sum(int num)
{
//completa el método recursivo
if (num == 5) {
return 5;
}
return num + Sum(num + 5);

}
}
}