How to Sum Up an Array of Integers in C#

How to sum up an array of integers in C#

Provided that you can use .NET 3.5 (or newer) and LINQ, try

int sum = arr.Sum();

sum up an array of integers in C#

It isn't clear what you want... If you want to sum some numbers so that the sum stops summing when it reaches 1002 you can:

List<int> list = new List<int> { 4, 900, 500, 498, 4 };
var lst = list.Skip(2).Take(3);

int sum = 0;

foreach (int num in lst)
{
    int sum2 = sum + num;

    if (sum2 > 1002)
    {
        break;
    }

    sum = sum2;
}

Console.WriteLine(sum);

or you can

List<int> list = new List<int> { 4, 900, 500, 498, 4 };
var lst = list.Skip(2).Take(3);

int sum = 0;

foreach (int num in lst)
{
    sum += num;

    if (sum >= 1002)
    {
        break;
    }
}

Console.WriteLine(sum);

The first one will stop if by adding a number it would go over 1002, while the second will stop AFTER reaching 1002.

Note that both of these can't be easily done directly in LINQ.

Sum of selected values in an int Array in c#

If I understand it correct and using your code this is what you want.

        int[] numbers = new int[] { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
        int sum = 1 + 2;
        int total=0;

        foreach (int n in numbers)
        {
            if (n % 3 == 0 || n % 5 == 0)
            {
                int total += n;
            }
            else
            {
                Console.WriteLine("not divisible");
            }
        }
        Console.WriteLine(total);

I moved the printing out to after the foreach so you get one result when it is done

Array.Sum() results in an overflow

The issue is that while the individual values fit within an int, the sum of these numbers results is larger than an int can hold.

You therefore need to cast the values to long (or another datatype that takes numbers that big, but since you're using Int64...):

long sum = arr.Sum(v => (long)v);

Array of total even numbers

You are checking the parity of the loop index i. Use nums[i] in your for loop instead:

if (nums[i] % 2 == 0)
// ... rest of code

Is it possible to sum all integers in a list? (C# console)

The other answer recommends LINQ, and that is definitely the less verbose way to do it. But I have a feeling that you're just learning, so may want to have an idea of how this actually works. Below is the an abridged version of the Linq.Sum source code so you can see what is happening.

public static int Sum(this IEnumerable<int> source)
{
    int sum = 0;
    foreach (int v in source)
    {
        sum += v;
    }
    return sum;
}

It loops through each item in the IEnumerable, adds them to another variable, and then returns that result.

---

Related Topics