Program to remove left factoring of grammar

Program to remove left factoring of grammar : 

#include<iostream.h>

#include<stdio.h>

#include<conio.h>

#include<string.h>

//Structure Declaration

struct production

{

            char lf;

            char rt[10];

            int prod_rear;

            int fl;

};

struct production prodn[20],prodn_new[20];     //Creation of object

//Variables Declaration

int b=-1,d,f,q,n,m=0,c=0;

char terminal[20],nonterm[20],alpha[10],extra[10];

char epsilon='^';

//Beginning of Main Program

void main()

{

   clrscr();

   //Input of Special characters

   cout<<"\nEnter the number of Special characters(except non-terminals): ";

   cin>>q;

   cout<<"Enter the special characters for your production: ";

   for(int cnt=0;cnt<q;cnt++)

   {

     cin>>alpha[cnt];

   }

   //Input of Productions

   cout<<"\nEnter the number of productions: ";

   cin>>n;

   for(cnt=0;cnt<=n-1;cnt++)

   {

     cout<<"Enter the "<< cnt+1<<" production: ";

     cin>>prodn[cnt].lf;

     cout<<"->";

     cin>>prodn[cnt].rt;

     prodn[cnt].prod_rear=strlen(prodn[cnt].rt);

     prodn[cnt].fl=0;

   }

   //Condition for left factoring

   for(int cnt1=0;cnt1<n;cnt1++)

   {

     for(int cnt2=cnt1+1;cnt2<n;cnt2++)

     {

            if(prodn[cnt1].lf==prodn[cnt2].lf)

            {

              cnt=0;

              int p=-1;

              while((prodn[cnt1].rt[cnt]!='\0')&&(prodn[cnt2].rt[cnt]!='\0'))

              {

                if(prodn[cnt1].rt[cnt]==prodn[cnt2].rt[cnt])

                {

                  extra[++p]=prodn[cnt1].rt[cnt];

                  prodn[cnt1].fl=1;

                  prodn[cnt2].fl=1;

                }

                else

                {

                  if(p==-1)

                          break;

                  else

                  {

                          int h=0,u=0;

                          prodn_new[++b].lf=prodn[cnt1].lf;

                          strcpy(prodn_new[b].rt,extra);

                          prodn_new[b].rt[p+1]=alpha[c];

                          prodn_new[++b].lf=alpha[c];

                          for(int g=cnt;g<prodn[cnt2].prod_rear;g++)

                           prodn_new[b].rt[h++]=prodn[cnt2].rt[g];

                           prodn_new[++b].lf=alpha[c];

                          for(g=cnt;g<=prodn[cnt1].prod_rear;g++)

                           prodn_new[b].rt[u++]=prodn[cnt1].rt[g];

                           m=1;

                           break;

                   }

                 }

                 cnt++;

               }

               if((prodn[cnt1].rt[cnt]==0)&&(m==0))

               {

                         int h=0;

                         prodn_new[++b].lf=prodn[cnt1].lf;

                         strcpy(prodn_new[b].rt,extra);

                         prodn_new[b].rt[p+1]=alpha[c];

                         prodn_new[++b].lf=alpha[c];

                         prodn_new[b].rt[0]=epsilon;

                         prodn_new[++b].lf=alpha[c];

                         for(int g=cnt;g<prodn[cnt2].prod_rear;g++)

                         prodn_new[b].rt[h++]=prodn[cnt2].rt[g];

               }

               if((prodn[cnt2].rt[cnt]==0)&&(m==0))

               {

                 int h=0;

                 prodn_new[++b].lf=prodn[cnt1].lf;

                 strcpy(prodn_new[b].rt,extra);

                 prodn_new[b].rt[p+1]=alpha[c];

                 prodn_new[++b].lf=alpha[c];

                 prodn_new[b].rt[0]=epsilon;

                 prodn_new[++b].lf=alpha[c];

                 for(int g=cnt;g<prodn[cnt1].prod_rear;g++)

                  prodn_new[b].rt[h++]=prodn[cnt1].rt[g];

               }

               c++;

               m=0;

             }

       }

    }

   //Display of Output

    cout<<"\n\n********************************";

    cout<<"\n      AFTER LEFT FACTORING      ";

    cout<<"\n********************************";

    cout<<endl;

    for(int cnt3=0;cnt3<=b;cnt3++)

            {

                        cout<<"Production "<<cnt3+1<<" is: ";

                        cout<<prodn_new[cnt3].lf;

                        cout<<"->";

                        cout<<prodn_new[cnt3].rt;

                        cout<<endl<<endl;

            }

    for(int cnt4=0;cnt4<n;cnt4++)

    {

    if(prodn[cnt4].fl==0)

    {

    cout<<"Production  "<<cnt3++<<" is: ";

    cout<<prodn[cnt4].lf;

    cout<<"->";

    cout<<prodn[cnt4].rt;

    cout<<endl<<endl;

    }

  }

 getche();

}    //end of main program