Sum C# with Example

The Enumerable.Sum extension method calculates the sum of numeric values. 
In case the collection's elements are themselves numbers, you can calculate the sum directly. 
int[] numbers = new int[] { 1, 4, 6 }; 
Console.WriteLine( numbers.Sum() ); //outputs 11 
In case the type of the elements is a complex type, you can use a lambda expression to specify the value that 
should be calculated: 
var totalMonthlySalary = employees.Sum( employee => employee.MonthlySalary ); 
Sum extension method can calculate with the following types: 
Int32 
Int64 
Single 
Double 
Decimal 
In case your collection contains nullable types, you can use the null-coalescing operator to set a default value for 
null elements: 
int?[] numbers = new int?[] { 1, null, 6 }; 
Console.WriteLine( numbers.Sum( number => number ?? 0 ) ); //outputs 7