For loop help

Question

Hi again...another question I’m stumped on.

The program you are given takes a positive number N as input.
Complete the program to calculate the sum of all numbers from 1 to N inclusive.

Sample Input
4

Sample Output
10

Hint: Counter should start at 1

// question already has this typed out

Int N= Convert.ToInt32(Console.ReadLine());
Int sum = 0;
/* then further down it is typed

Console.WriteLine(sum); */

// what I have typed

For (sum = 0; sum > N; sum ++)
{
Console.WriteLine(sum);
}

Any help would be greatly appreciated. Thank you

Answer 1

without for loop:
int N= Convert.ToInt32(Console.ReadLine());
Console.WriteLine(N(N+1)/2);

with for loop:
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 N= Convert.ToInt32(Console.ReadLine());
int sum = 0;
for(int i = 0; i <= N; i++)
{
sum += i;
}
Console.WriteLine(sum);
}
}
}

Answer 2

int sum = 0;
for(int i = 0; i <= N; i++)
{
sum += i;
}

the for loop will run until i <= N is true and each time we are adding i to sum and incrementing i by 1.

for example if N = 4
i = 0
sum = sum + i
= 0 + 0
= 0
i++

i = 1
sum = sum + i
= 0 + 1
= 1
i++

i = 2
sum = sum + i
= 1 + 2
= 3
i++

i = 3
sum = sum + i
= 3 + 3
= 6
i++

i = 4
sum = sum + i
= 6 + 4
= 10
i++

i=5 which makes our i<=N(5<=4) condition false and therefore the for loop stops executing

so our final sum value is 10.

Answer 3

RKK thank you!!!!!! :)

Answer 4

RKK thank you for the help ! it’s much appreciated,would you mind explaining how that for loop worked?