C# question

string number = null;while (number == null){	Console.Write("Enter a number:");	number = Console.ReadLine().Trim();	int temp;	if (int.TryParse(number, out temp) == false)	{		number = null;	}}StringBuilder reverseNumber = new StringBuilder();int total = 0;for (int index = number.Length - 1; index >= 0; index--){	reverseNumber.Append(number[index].ToString());	total += int.Parse(number[index].ToString());}Console.WriteLine(string.Format("Reverse={0}, Sum={1}", reverseNumber.ToString(), total));

int number = 1515; // From user inputint reversed = 0;int crossFoot = 0;while (number > 0){    int digit = number % 10;    number /= 10;    crossFoot += digit;    reversed += digit;    reversed *= 10;}reversed /= 10;Console.WriteLine(string.Format("Reverse={0}, CrossFoot={1}", reversed, crossFoot));

using System;public class proj1{    public static void Main()    {        Console.Write("Enter a 4 digit number: ");        string nums = Console.ReadLine();        int numbers = Convert.ToInt32(nums);        char n = nums[3];        char n1 = nums[2];        char n2 = nums[1];        char n3 = nums[0];        int s = Convert.ToInt32(n);        int s1 = Convert.ToInt32(n1);        int s2 = Convert.ToInt32(n2);        int s3 = Convert.ToInt32(n3);        int total = (s + s1 + s2 + s3);        int num = numbers % 10;        int num1 = numbers / 10;        Console.Write("\nReversed: ");        Console.Write(num);        Console.WriteLine(num1);        Console.Write("Sum of digits: ");        Console.Write(total);        Console.ReadLine();    }}