In this program, You will learn how to find the sum of prime numbers between 1 to n in C#.

`10th => 2 + 3 + 5 + 7 = 17`

## Example: How to find the sum of prime numbers between 1 to n in C#.

```
using System;
public class Program
{
public static void Main(string[] args)
{
int n, i, p, k, s = 0;
Console.Write("Enter a number:");
n = Convert.ToInt32(Console.ReadLine());
for (i = 2; i <= n; i++)
{
k = 2;
p = 1;
while (k < i)
{
if (i % k == 0)
{
p = 0;
break;
}
k++;
}
if (p == 1)
{
s = s + i;
}
}
Console.WriteLine("Sum of prime numbers:" + s);
}
}
```

#### Output:

```
Enter a number:10
Sum of prime numbers:17
```