Program to find first and follow of non terminals in a grammer

firstfollow.c

#include<stdio.h>
#include<string.h>
/*******/
// row 1 : no of rules
// rows>1: production rules
/*******/
int p;
char NTERM[20];
char LHS[20];
char RHS[20][10];

int containsE(char *str){
    int contains=0,l=strlen(str);
    while(l-->0){
        if(str[l]=='E'){
            contains=1;
            break;
        }
    }
    return contains;
}
void append(char *str, char ch){
    // printf("append(%s,%c)",str,ch);
    int i=0,l=strlen(str);
    for(i=0;i<l;i++){
        if(str[i]==ch){
            return;
        }
    }
    str[l]=ch;
    str[l+1]='\0';
    // printf("=%s\n",str);
}
void strcpyUnique(char *str1, char *str2 ,int blockE){
    // printf("strcpyUnique(%s,%s)",str1,str2);
    int l1=strlen(str1);
    int l2=strlen(str2);
    int i,j,occurance;
    for(i=0;i<l2;i++){
        if(str2[i]=='E' && blockE) continue;
        occurance=0;
        for(j=0;j<l1;j++){
        	if(str1[j]==str2[i]) {
                occurance=1;
                break;
            }   
        }
        if(occurance==0) str1[l1++]=str2[i];
    }
    str1[l1]='\0';
    // printf("=%s\n",str1);
}
void first(char lhs, char* RESULT){
    char FIRST[10]="",copy[10];
	int index=0,i,j;
	for(i=0;i<p;i++){
        j=0;
		if(lhs==LHS[i]){
            if(RHS[i][0]!='E'){
                if(RHS[i][0]<'A' || RHS[i][0]>'Z'){
                    append(FIRST,RHS[i][0]);
                }
                else{ // rule gave non terminal
                    first(RHS[i][j],copy);
                    while(containsE(copy)){
                        if(RHS[i][++j]=='\0'){
                            strcpyUnique(FIRST,copy,0);
                            break;
                        }
                        strcpyUnique(FIRST,copy,1);
                        first(RHS[i][j],copy);
                    }
                    if(containsE(copy)==0){
                        strcpyUnique(FIRST,copy,1);
                    }
                }
		    }
            else{
                append(FIRST,'E');
            }
        }
	}
    strcpy(RESULT,FIRST); // done
    // printf("first(%c)=%s\n",lhs,RESULT);
}
void follow(char nterm,char *RESULT){
	// printf("Follow(%c)\n",nterm);
    char FOLLOW[10]="",copy[10]={0};
    if(nterm==LHS[0])
    	append(FOLLOW,'$');
    int i,j,k=1;
    for(i=0;i<p;i++){
        for(j=0;RHS[i][j]!='\0';j++){
            if(nterm==RHS[i][j]){
                while(1){
                    if(RHS[i][j+1]=='\0'){
                        if(LHS[i]!=RHS[i][j]){
                            follow(LHS[i],copy);
                            strcpyUnique(FOLLOW,copy,1);
                        }
                        break;
                    }
                    else if(RHS[i][j+1]>='A' && RHS[i][j+1]<='Z'){
                        // append(FOLLOW,'^');
                        first(RHS[i][j+1],copy);
                        strcpyUnique(FOLLOW,copy,1);
                        if(containsE(copy)){
                            j++;
                        }else{
                            break;
                        }
                    }
                    else{
                        append(FOLLOW,RHS[i][j+1]);
                        break;
                    }
                }
            }
        }
    }
    strcpy(RESULT,FOLLOW);
	// printf("Follow(%c)=%s\n",nterm,RESULT);
}
int main(){
	int i,j;
    char FIRST[10][10]={0},FOLLOW[10][10]={0};
	scanf("%d",&p);
	for(i=0;i<p;i++){
		scanf(" %c->%s",&LHS[i],RHS[i]);
	}
	int store=0,bit,n=0;
	for(i=0;i<p;i++){
		bit=1<< (LHS[i]-'A');
		if((store&bit)!=0){
			continue;
		}
		store|=bit;
		NTERM[n++]=LHS[i];
	}
	for(i=0;i<n;i++){
        first(NTERM[i],FIRST[i]);
		printf("FIRST(%c) : %s\n",NTERM[i],FIRST[i]);
	}
    for(i=0;i<n;i++){
        follow(NTERM[i],FOLLOW[i]);
        printf("FOLLOW(%c) : %s\n",NTERM[i],FOLLOW[i]);
    }
	return 0;
}