# Write a program in C# to find the largest prime among a collection of numbers

Posted by Rajnilari2015 under C# category on | Points: 40 | Views : 1004
Let's say that we have a collection of integers as {104723, 104729, 9998,448 }. Objective is to find the largest prime among a collection of numbers. The below program will do so

`using System;using System.Collections.Generic;using System.Linq;namespace ConsoleApplication1{    class Program    {        static void Main(string[] args)        {            var numberCollection = new List<int>() {104723, 104729, 9998,448 };            var nonPrimeCollection = new List<int>();            for (int j = 0; j < numberCollection.Count; j++)            {                for (int i = 2; i < numberCollection[j]; i++)                {                    if (numberCollection[j] % i == 0)                    {                                               nonPrimeCollection.Add(numberCollection[j]);                        break;                    }                }                            }            Console.WriteLine("Largest Prime {0} ", numberCollection.Except(nonPrimeCollection).Max());            Console.ReadKey();        }    }}Result--------Largest Prime 104729`

The outer for loop is looping thru the entire collection. The inner for loop starts at 2 and picks up those elements that are not primes. And then we are finding the numbers which are prime and finally finding the max.