using System;

public class Program

{

​

​

    public static void Main(String[] args) {

​

        Test("1:420+4:9####", "42091234");

        Test("1:420+4:9####", "4209123A");

​

    }

    static void Test(string format, string value)

    {

        Console.WriteLine("format: {0}, value: {1}, result:{2}", format, value, CheckFormat(format, value));

    }

    static bool CheckFormat(string formatString, string value)

    {

        string[] tests = formatString.Split('+');

        foreach(string test in tests)

        {

            string[] testElement = test.Split(':');

            int startPos = int.Parse(testElement[0]);

            string patterns = testElement[1];

            string[] patternElements = patterns.Split(',');

            foreach(string patternElement in patternElements)

            {

                //value string not long enough, so fail.

                if(startPos + patternElement.Length > value.Length)

                    return false;

                for (int i = 0; i < patternElement.Length; i++)

                {

                    switch(patternElement[i])

                    {

                        case '#':

                            if (!Char.IsNumber(value[i]))

                                return false;

                            break;

​

                        case '&':

​

                            if (!Char.IsLetter(value[i]))

                                return false;

                            break;

                        default:

                            if(patternElement[i] != value[i])

                                return false;

                            break;

                    }

                }

            }

        }

        return true;

    }

​

}