Update Lookup Field Programmatically in SharePoint

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint.Client;
using System.Data;
using Microsoft.SharePoint;
namespace ConsoleApplication5 {
    class Program {
        static void Main(string[] args) {
            ClientContext context = new ClientContext("siteName");
            // ListName - child List of Lookup column
            List list = context.Web.Lists.GetByTitle("ListName");
            ListItem item;
            context.Load(list);
            context.ExecuteQuery();
            string strLookupValue = "LookupValue";
            if (strLookupValue != "") {
                try {
                    //LookupList - name of parent list from which we taking value
                    List lookuplist = context.Web.Lists.GetByTitle("LookupList");
                    item["LookColumnName"] = GetLookFieldIDS(context, strLookupValue, lookuplist);
                } catch (Exception e) {
                    item["LookColumnName"] = "";
                    Console.WriteLine(e.Message);
                    Console.ReadLine();
                }
            } else {
                item["LookColumnName"] = "";
            }
            item.Update();
            context.ExecuteQuery();
        }
        public static SPFieldLookupValueCollection GetLookFieldIDS(ClientContext context, string lookupValues, List lookupSourceList) {
            SPFieldLookupValueCollection lookupIds = new SPFieldLookupValueCollection();
            string[] lookups = lookupValues.Split(new char[] {
                    ','
                },
                StringSplitOptions.RemoveEmptyEntries);
            foreach(string lookupValue in lookups) {
                CamlQuery query = new CamlQuery();
                query.ViewXml = string.Format("<View><Query><Where><Eq><FieldRef Name='Title'/><Value Type='Text'>{0}</Value></Eq></Where></Query></View>", lookupValue);
                ListItemCollection listItems = lookupSourceList.GetItems(query);
                context.Load(lookupSourceList);
                context.Load(listItems);
                context.ExecuteQuery();
                foreach(ListItem item in listItems) {
                    SPFieldLookupValue value = new SPFieldLookupValue(Convert.ToInt32(item["ID"]), item["Title"].ToString());
                    lookupIds.Add(value);
                    break;
                }
            }
            return lookupIds;
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint.Client;
using System.Data;
using Microsoft.SharePoint;
namespace ConsoleApplication5 {
    class Program {
        static void Main(string[] args) {
            SPSite site = new SPSite("SiteName");
            SPWeb mySite = site.OpenWeb();
            //ListName - child List of Lookup column
            SPList list = mySite.Lists["ListName"];
            SPItem item;
            SPQuery query = new SPQuery();
            SPListItemCollection itemcoll;
            string strLookupValue = "LookupValue";
            if (strLookupValue != "") {
                try {
                    SPSite site1 = new SPSite("SiteName");
                    SPWeb web1 = site1.OpenWeb();
                    //LookupList - parent Lokkuplist
                    SPList list1 = web1.Lists["LookupList"];
                    query.Query = "<Where><Eq><FieldRef Name='Title' /><Value Type='Text'>" + strLookupValue + "</Value></Eq></Where>";
                    itemcoll = list1.GetItems(query);
                    SPFieldLookupValue newValue = new SPFieldLookupValue(Convert.ToInt32(itemcoll[0].ID), strLookupValue);
                    item["LookupColumnName"] = newValue;
                } catch (Exception e) {
                    item["LookupColumnName"] = "";
                }
            } else {
                item["LookupColumnName"] = "";
            }
        }
    }
}