using System;
using System.Text.RegularExpressions;
public class CheckStringValidFrmatXXX_XXX_XXXX_CSharp {
public static void Main(string[] args) {
string s = "771-290-1652";
if (IsValidFormat(s)) {
Console.WriteLine("Valid");
} else {
Console.WriteLine("Not Valid");
}
s = "771-29-162";
if (IsValidFormat(s)) {
Console.WriteLine("Valid");
} else {
Console.WriteLine("Not Valid");
}
s = "771-AB1-1620";
if (IsValidFormat(s)) {
Console.WriteLine("Valid");
} else {
Console.WriteLine("Not Valid");
}
}
private static bool IsValidFormat(string s) {
string pattern = @"(\d{3}-)?\d{3}-\d{4}";
return Regex.IsMatch(s, pattern);
}
}
/*
run:
Valid
Not Valid
Not Valid
*/
