A + B Problem II

using System;
using System.Text;

namespace TestSum
{
    class Program
    {
        static void Main(string[] args)
        {
            long a = 112233445566778899;
            long b = 998877665544332211;

            //long a = 123;
            //long b = 29;

            char[] ac = a.ToString().ToCharArray();
            char[] bc = b.ToString().ToCharArray();
            StringBuilder result = new StringBuilder();
            if(ac.Length>=bc.Length)
            {

                int temp = 0;

                for (int i = ac.Length - 1, j = bc.Length-1; i>=0; i--,j--)
                {
                    
                    int indexValue = 0;

                    if (temp == 1)
                    {
                        indexValue++;
                    }
                    int _a = 0, _b = 0;
                    if(j<0)
                    {
                        _b = 0;
                        _a = int.Parse(ac[i].ToString());
                    }
                     else
                    {
                        _a = int.Parse(ac[i].ToString());
                        _b = int.Parse(bc[j].ToString());
                    }
     
                    if(_a+_b>9)
                    {
                        indexValue+= ((_a + _b-10 ));
                        temp = 1;
                    }
                    else
                    {
                        indexValue+= (_a + _b);
                        temp = 0;
                    }

                    

                    result.Append(indexValue);
                }
            }

          reverse(result.ToString());
            Console.ReadKey();

        
        }

       static void reverse(string result)
        {
            for(int i =result.Length-1;i>=0;i--)
            {
                Console.Write(result[i]);
            }
        }
    }
}