Program to eliminate unit productions from given CFG (context free grammar). - Java program

Write a program to eliminate unit productions from given CFG.

Program:

package engineeringway;

import java.io.BufferedReader;

import java.io.FileNotFoundException;

import java.io.FileReader;

import java.io.IOException;

import java.util.ArrayList;

import java.util.List;

public class engineeringway {

 /**

     * @param args the command line arguments

     */

   public static void main(String[] args) throws FileNotFoundException, IOException {

       // TODO code application logic here

       BufferedReader in = new BufferedReader(new FileReader("E://sid//input4.txt"));

        String str;

        List<String> list = new ArrayList<String>();

while((str = in.readLine()) != null){

list.add(str);

        }

String[] stringArr = list.toArray(new String[0]);

int i=0;

int j=0;

int c=0;

for(i=0;i<stringArr.length;i++){

System.out.println(stringArr[i].length());

if(stringArr[i].length()==3){

c++;

        }

        }

StringBuilder[] pro1=new StringBuilder[c];

StringBuilder[] pro2=new StringBuilder[stringArr.length];

for(i=0;i<stringArr.length;i++){

pro2[i] = new StringBuilder("");

pro2[i].append(stringArr[i]);

System.out.println("-"+pro2[i]);

if(stringArr[i].length()==3){

pro1[j] = new StringBuilder("");

System.out.println(stringArr[i]);

pro1[j].append(stringArr[i]);

j++;

        }

        }

System.out.print("\n");

int count=0;

for(int b=0;b<pro1.length;b++)

            {

                String b1;

                b1=pro1[b].toString().trim();

                String c1=b1.substring(b1.length() - 1);

char ch = c1.charAt(0);

                //System.out.println(ch);

if(ch>='A' &&ch<='Z'){

System.out.println(pro1[b]);

count++;

for(int q=0;q<pro2.length;q++){

char first=pro2[q].toString().charAt(0);

System.out.println(first);

if(ch==first){

                            //for(int r=0;r<pro2[q].length();r++)

                            //{

System.out.println(pro2[q].substring(2));

                                String sub=pro2[q].substring(2);

for(int r=0;r<pro2.length;r++){

if(pro2[r].length()==3 && pro2[2].toString().charAt(0)==ch){

 String h=pro2[r].toString().replaceAll(String.valueOf(pro2[2].toString().charAt(0)),sub    pro2[r].replace(0, pro2[r].length(), h )}  }

}     }

    }

  }

for(int r=0;r<pro2.length;r++){

System.out.println(pro2[r]);

            }

if(count==0){

System.out.println("Unit production doesn't exist");

        }

else{

System.out.println("Unit production exist");

        }

  }

}

Output: