program.cs

a compiler in java that parses and creates lexer analyzer

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace Scanner
{
    class Program
    {
        public static String[,] collection = new String[,] { { "BEGIN", "1" }, { "END", "1" }, { "LET", "1" }, { "READ", "1" }, { "WRITE", "1" }, { "IF", "1" }, { "FI", "1" }, { "ELSE", "1" }, { "WHILE", "1" }, { "WEND", "1" }, { "+", "2" }, { "-", "2" }, { "*", "2" }, { "/", "2" }, { "%", "2" } };
        public static String[] tokens = new String[] { "identifier", "keyword", "operand" };
        
        static void Main(string[] args)
        {
            /*this code simply reads a file and then replaces all the contents in the file
             *with their equivalents in the programming language in another output file.
             */
            
            //take input file name from the current directory
                Console.Clear();
                String file_name, input;    

                Console.WriteLine("\n\t-< SIMPLE SCANNER >-");
                
                if (args.Length == 0)
                {
                    Console.Beep();
                    Console.WriteLine("Too Many/few Parameters");
                    Console.Write("Enter a valid .in file:");
                    file_name = Console.ReadLine();
                }

                else 
                {
                    file_name = args[0];
                }
                if (!File.Exists(file_name))
                {
                    Console.Beep();
                    Console.WriteLine("ERROR: FILE NOT FOUND");
                }//endIF
                
                //readfile and then create a variable output and then append the output 
                //to the variable, finally write the output variable to .out file.
                StreamReader stream = new StreamReader(file_name);
                input = stream.ReadToEnd();
                Console.WriteLine("\n\nFile Data:\n-----------------------\n");
                Console.WriteLine(input);
                String [] words = new String[100];
                char [] sep = new char[]{' '};
                words = input.Split(sep);
                Console.WriteLine("\n\nScanned Tokens:\n--------------------\n");
                foreach (string str in words)
                {
                    String index = "";
                    index = find(str);
                    Console.Write("{0} ", replace(index));
                }



                Console.ReadKey();
        }//endMAIN
        public static string find(string str)
        {
            string index = "0";

            for (int n = 0; n < collection.GetLength(0); n++)
            {
                if (str.CompareTo(collection[n,0]) == 0)
                {
                    index = collection[n,1];
                    return(index);
                }
            }
            return "0";
        }
        public static string replace(string index)
        { 
            int ind = Convert.ToInt32(index);
            return (tokens[ind]);
        }
        
    }//endClassProgam

}//endNAMESPACEScanner