using System; using SomePackageName.Tokenizers; public class Example { public static void Main(string[] args) { string input = "123456789"; ITokenizer tokenizer = new SimpleTokenizer(input); if (tokenizer.NextIs(TokenTypes.NUMBER)) { Console.WriteLine("The next token is a number."); } else { Console.WriteLine("The next token is not a number."); } } }In this example, we are using the NextIs method to check whether the next token in the input string is a number or not. If it is a number, then the program prints "The next token is a number", otherwise it prints "The next token is not a number". The package/library used in this example is SomePackageName.Tokenizers, which could be a custom package or library specific to the project. The specific implementation of the tokenizer used in this example is SimpleTokenizer.