using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.SharePoint;
using System.Collections;
 
namespace CalculatedField
{
    class Program
    {
        static void Main(string[] args)
        {
            using (SPSite site = new SPSite("http://serverName/sites/Vijai/"))
            {
                using (SPWeb web = site.OpenWeb())
                {
                    SPList list = web.Lists.TryGetList("Custom");
                    if (list != null)
                    {
                        ////Create a calculated field
                        string calculatedColumn = list.Fields.Add("CalculatedColumn", SPFieldType.Calculated, false);
                        ////Get the newly created calculated field
                        SPFieldCalculated calculatedField = list.Fields[calculatedColumn] as SPFieldCalculated;
                        ////Set the calculated field formula
                        calculatedField.Formula = "=[Title]";
                        ////Set the data type returned from this formula
                        calculatedField.OutputType = SPFieldType.Text;
                        ////Update the calculated field
                        calculatedField.Update();
                    }
                }
            }
        }
    }
}