int myNumber = 010;
string myString = myNumber.ToString("D3");
Console.Write(myString);
/* D represents 'Decimal', and 3 is the specified amount of digits you want
the number to always be. This will pad your value with zeroes until it
reaches 5 digits.*/
using System;
public class Program
{
public static void Main()
{
int num = 50;
string paddedNum = num.ToString().PadLeft(5, '0');
Console.WriteLine(paddedNum);
}
}