Random telephone number generator using C#

Question

hi  i want to generate a random telephone number of the format XXX-XXX-XXXX using C#  the first 3 digits should not contain 89 and the second 3 digits should not contain number more than 742. please help

Alan · Answer

This code should do it: using System; using System.Text; class Program { static Random rand = new Random(); static void Main() { for (int i = 0; i { Console.WriteLine(GetRandomTelNo()); } Console.ReadLine(); } static string GetRandomTelNo() { StringBuilder telNo = new StringBuilder(12); int number; for (int i = 0; i { number = rand.Next(0 8); // digit between 0 (incl) and 8 (excl) telNo = telNo.Append(number.ToString()); } telNo = telNo.Append(-); number = rand.Next(0 743); // number between 0 (incl) and 743 (excl) telNo = telNo.Append(String.Format({0:D3} number)); telNo = telNo.Append(-); number = rand.Next(0 10000); // number between 0 (incl) and 10000 (excl) telNo = telNo.Append(String.Format({0:D4} number)); return telNo.ToString(); } }