1.sum of array: using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace ConsoleApplication2 { class Program { static void Main(string[] args) { int[] arr = { 1, 2, 3, 4, 5 }; int sum = 0; for(int i=0;i<arr.Length;i++) { sum += arr[i]; } Console.WriteLine("The sum of array:" + sum); Console.ReadLine(); } } } ............................................................................................................................................