How to Sum Up an Array of Integers in C#

1. Use the sum() Method to Sum Up Array of Integers in C#
2. Use the Array.foreach Method to Sum Up Array of Integers in C#
3. Use Enumerable.Aggregate() Method to Sum Up Array of Integers in C#

This article will introduce how to sum up an array of integers in C#.

Use the sum() Method to Sum Up Array of Integers in C#

IEnumerable is derived from the System.Collections.Generic namespace. It is an interface that defines a GetEnumerator function. It allows a loop through a collection of classes or lists of anonymous types.

The sum() method is an extension method found in the System.Linq namespace. This method sums up all numeric values in an IEnumerable like a list or an array.

The sum() method can be used on objects that implement IEnumerable with all C# numeric data types like int, long, double, and decimal. It is an optimized way of adding a collection of numbers by avoiding loops.

This method encourages fewer lines of code and possibly reduces bugs but has some overhead that makes it slower than the for loop.

Below is an example of code using sum().

using System;
using System.Linq;
namespace MyApplication {
  class Program {
    static void Main(string[] args) {
      int[] arr = new int[] { 1, 2, 3 };
      int sum = arr.Sum();
      Console.WriteLine(sum);
    }
  }
}

Output:

6

Use the Array.foreach Method to Sum Up Array of Integers in C#

The foreach statement is a neat and less complicated method of iterating through array elements. The foreach method processes elements of a single-dimensional array in increasing order, starting with the element at index 0 through the element at index array.length - 1.

A delegate is a type-safe and secure reference type. It is used to encapsulate a named or anonymous method.

A delegate must be instantiated with a method or lambda expression with a compatible return type. We use the lambda expression nested in a foreach statement.

Below is an example of code using a foreach method.

using System;
namespace MyApplication {
  class Program {
    static void Main(string[] args) {
      int[] arr = new int[] { 1, 2, 3 };
      int sum = 0;
      Array.ForEach(arr, i => sum += i);
      Console.WriteLine(sum);
    }
  }
}

Output:

6

Use Enumerable.Aggregate() Method to Sum Up Array of Integers in C#

The Enumerable.Aggregate method is present in the System.Linq namespace. It performs a mathematical operation on each element of a list or array while tracking or storing the previous result.

For instance, we have to perform an addition operation on an array or list of numbers {2,4,6,8}. The Aggregate function adds 2 and 4, carries the result (i.e. 6) forward, adds that result with the next element (6+6), carries the result forward, then adds it with the next element (12+8). It returns the final result when the last number is processed.

Below is an example of code.

using System;
using System.Linq;
namespace MyApplication {
  class Program {
    static void Main(string[] args) {
      int[] arr = new int[] { 1, 2, 3 };
      int sum = arr.Aggregate((total, next) => total + next);

      Console.WriteLine(sum);
    }
  }
}

Output:

6