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AIM: Write a  program for eliminating the left factoring of the given grammar.

Program:
#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;
	 }
		}
	}

OUTPUT:-