STRUCTURE PROGRAMMING AND COMPILER CODE

STRUCTURE PROGRAMMING AND COMPILER CODE

1.FIRST AND FOLLOW

2.ELIMINATION OF LEFT RECURSION

3.SHIFT REDUCE PARSER

4.CODE OPTIMISATION

5.2 PASS ASSEMBLER

          input.txt

6.LEXICAL ANALYSER

         lexinput.txt

7.2 PASS MACRO

         input.txt

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input.txt

MACRO

INCR &ARG1,&ARG2,&ARG3

A 1,&ARG1

A 2,&ARG2

A 3,&ARG3

MEND

INCR DATA1,DATA2,DATA3

INCR DATA2,DATA3,DATA1

DATA1 DC F'5'

DATA2 DC F'10'

DATA3 DC F'15'

END

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2 PASS MACRO

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

typedef struct mdt_table{

int index;

char card[30];

}MDT;

typedef struct mnt_table{

int index;

char name[15];

int mdtindex;

}MNT;

typedef struct ala_table{

char index[3];

char arg[15];

}ALA;

typedef struct ala_array{

ALA item[5];

}ALA_ITEM;

MNT mnt[5];

MDT mdt[40];

ALA ala[5];

int mdtc,mntc,mdtp,alac,alap;

char word3[10],ch3[2],word[10],line[20],ch,ch1[2],ch2[2],line1[20],line2[20],k;

FILE *input,*inter,*output;

fpos_t pos;

char* num[5]={"#1","#2","#3","#4","#5"};

void get_word(){

int i=0;

//char ch;

ch=getc(input);

while(ch!=EOF){

if((ch!=' ')&&(ch!=',')&&(ch!='\n'))

word[i++]=ch;

if((ch==' ')||(ch==',')||(ch=='\n')){

word[i]='\0';

break;

}

ch=getc(input);

}

}

void display_mnt(){

int i=0;

printf("\nMNT\n");

for(i=0;i<mntc;i++){

printf("%d\t%s\t%d",mnt[i].index,mnt[i].name,mnt[i].mdtindex);

printf("\n");

}

}

void display_mdt(){

int i=0;

printf("\nMDT\n");

for(i=0;i<mdtc;i++){

printf("%d\t%s",mdt[i].index,mdt[i].card);

printf("\n");

}

}

void display_ala(){

int i=0;

printf("\nALA\n");

for(i=0;i<alac;i++){

printf("%s\t%s",ala[i].index,ala[i].arg);

printf("\n");

}

}

void display_ala_item(ALA_ITEM obj){

int i;

printf("\nALA ITEM\n");

for(i=0;i<alap;i++){

printf("%s\t%s",obj.item[i].index,obj.item[i].arg);

printf("\n");

}

}

void search_ALA(){

int i;

for(i=0;i<alac;i++){

if(strcmp(word,ala[i].arg)==0){

strcpy(word,ala[i].index);

}

}

}

void PASS1(){

int i;

input=fopen("input.txt","r");

inter=fopen("inter.txt","w+");

mdtc=mntc=alac=0;

while(!feof(input)){

fgetpos(input,&pos);

get_word();

/*printf("%s\n",word);

fprintf(inter,"%s\n",word);*/

if(strcmp(word,"MACRO")!=0){

fsetpos(input,&pos);

fgets(line,20,input);

fprintf(inter,"%s",line);

}

if(strcmp(word,"MACRO")==0){

fgetpos(input,&pos);

get_word();

//mnt

//printf("%s",word);

strcpy(mnt[mntc].name,word);

mnt[mntc].index=mntc;

mnt[mntc].mdtindex=mdtc;

mntc++;

display_mnt();

//mdt

fsetpos(input,&pos);

i=0;

//enter arg line into mdt

while(!feof(input)){

ch=getc(input);

if(ch=='\n'){

line[i]='\0';

break;

}

line[i++]=ch;

}

//enter into mdt

//printf("%s",line);

mdt[mdtc].index=mdtc;

strcpy(mdt[mdtc].card,line);

mdtc++;

display_mdt();

//setup ala

fsetpos(input,&pos);

get_word();

do{

get_word();

strcpy(ala[alac].arg,word);

strcpy(ala[alac].index,num[alac]);

alac++;

}while(ch!='\n');//this is why ch is global

display_ala();

fgetpos(input,&pos);

get_word();

ch1[0]=ch;

ch1[1]='\0';

//printf("%s%s\n",word,ch1);

while(strcmp(word,"MEND")!=0){

//clear the array

memset(line1,0,strlen(line1));

do{

search_ALA();

strcat(line1,word);

strcat(line1,ch1);

//printf("\n%s",line1);

get_word();

ch1[0]=ch;

}while(ch1[0]!='\n');

search_ALA();

strcat(line1,word);

//strcat(line1,ch1);

mdt[mdtc].index=mdtc;

strcpy(mdt[mdtc].card,line1);

mdtc++;

get_word();

ch1[0]=ch;

}

//to enter mend to mdt

mdt[mdtc].index=mdtc;

strcpy(mdt[mdtc].card,word);

mdtc++;

display_mdt();

}

}

fclose(input);

fclose(inter);

}

int search_MNT(){

int i;

for(i=0;i<mntc;i++){

if(strcmp(word,mnt[i].name)==0){

mdtp=mnt[i].mdtindex;

return mnt[i].index;

}

}

return -1;

}

void get_word_line(){

int i=0;

ch3[1]='\0';

ch3[0]=line1[k];

memset(word3,0,strlen(word));

while(ch3[0]!='\0'){

if((ch3[0]!=' ')&&(ch3[0]!=',')&&(ch3[0]!='\0'))

word3[i++]=ch3[0];

if((ch3[0]==' ')||(ch3[0]==',')||(ch3[0]=='\0')){

word3[i]='\0';

break;

}

k++;

ch3[0]=line1[k];

}

}

void search_ALA_ITEM(ALA_ITEM obj){

int i;

for(i=0;i<alap;i++){

if(strcmp(word3,obj.item[i].index)==0){

memset(word3,0,strlen(word3));

strcpy(word3,obj.item[i].arg);

}

}

}

void PASS2(){

int f,i;

input=fopen("inter.txt","r");

output=fopen("output.txt","w+");

memset(word,0,strlen(word));

memset(line,0,strlen(line));

while(!feof(input)){

get_word();

ch2[0]=ch;

ch2[1]='\0';

//printf("%s%s",word,ch2);

//search in mnt

f=search_MNT();

//if not in mnt

if(f==-1){

fprintf(output,"%s%s",word,ch2);

if(strcmp(word,"END")==0)break;

}

else{

//setup ala

alap=0;

//for every call, new ALA_ITEM object

ALA_ITEM obj;

do{

get_word();

strcpy(obj.item[alap].index,num[alap]);

strcpy(obj.item[alap].arg,word);

alap++;

}while(ch!='\n');

//display the current ALA_ITEM object

display_ala_item(obj);

mdtp++;

while(strcmp(mdt[mdtp].card,"MEND")!=0){

memset(line1,0,strlen(line1));

strcpy(line1,mdt[mdtp].card);

//fprintf(output,"%s\n",line1);

k=0;

memset(line2,0,strlen(line2));

do{

get_word_line();

//printf("%s%s\n",word3,ch3);

k++;

//replace # with arg from corresponding ala

search_ALA_ITEM(obj);

//append to line

strcat(line2,word3);

strcat(line2,ch3);

}while(ch3[0]!='\0');

fprintf(output,"%s\n",line2);

mdtp++;

}

}

}

}

void main(){

PASS1();

PASS2();

}

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lexinput

#include<stdio.h>
void main()
{
int a,b,c;
printf("Enter");
while(a<b)
a=b+c;
c=a;
}

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LEXICAL ANALYSER

 #include<stdio.h>
#include<ctype.h>
#include<string.h>
void keyw(char *p);
int i=0,id=0,kw=0,num=0,op=0;
char keys[32][10]={"auto","break","case","char","const","continue","default",
"do","double","else","enum","extern","float","for","goto",
"if","int","long","register","return","short","signed",
"sizeof","static","struct","switch","typedef","union",
"unsigned","void","volatile","while"};
main()
{
    char ch,str[25],seps[15]=" \t\n,;(){}[]#\"<>",oper[]="!%^&*-+=~|.<>/?";
    int j;
    char fname[50];
    FILE *f1;
printf("enter file path (drive:\\fold\\filename)\n");
scanf("%s",fname);
f1 = fopen(fname,"r");
    if(f1==NULL)
    {
     printf("file not found");
     exit(0);
    }
    while((ch=fgetc(f1))!=EOF)
    {
for(j=0;j<=14;j++)
{
if(ch==oper[j])
{
printf("%c is an operator\n",ch);
op++;
str[i]='\0';
keyw(str);
}
}
for(j=0;j<=14;j++)
{
if(i==-1)
break;
if(ch==seps[j])
{
if(ch=='#')




{
while(ch!='>')
{
printf("%c",ch);
ch=fgetc(f1);
}
printf("%c is a header file\n",ch);
i=-1;
break;
}
if(ch=='"')
{
do
{
ch=fgetc(f1);
printf("%c",ch);
}while(ch!='"');
printf("\b is an argument\n");
i=-1;
break;
}
str[i]='\0';
keyw(str);
}
}
if(i!=-1)
{
str[i]=ch;
i++;
}
else
i=0;
    }
printf("Keywords: %d\nIdentifiers: %d\nOperators: %d\nNumbers: %d\n",kw,id,op,num);
}
void keyw(char *p)
{
int k,flag=0;
for(k=0;k<=31;k++)
{
if(strcmp(keys[k],p)==0)
{
printf("%s is a keyword\n",p);
kw++;
flag=1;



break;
}
}
if(flag==0)
{
if(isdigit(p[0]))
{
printf("%s is a number\n",p);
num++;
}
else
{
if(p[0]!='\0')
{
printf("%s is an identifier\n",p);
id++;
}
}
}
i=-1;
}

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INPUT.TXT

JOHN START 0
USING *,15
L 1,FIVE
A 1,FOUR
ST 1,TEMP
FOUR DC F'4'
FIVE DC F'5'
TEMP DS 2F
END

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2 PASS ASSEMBLER

#include<stdio.h>
#include<string.h>
#include<stdlib.h>

char POT[][7]={"START","USING","END"};
char MOT[][6]={"L","ST","A","S","M"};
char DEC[][4]={"DC","DS"};

typedef struct symbol{
char symbol[10];
int addr;
}SYMTAB;

SYMTAB sym[10];
int startaddr,lc,symcount=0,length;
char line[20],label[20],operand[20],opcode[20],prgname[20],op[4];


int search_POT(char opcode[]){
int i,j;

for(i=0;i<5;i++){
if(strcmp(opcode,POT[i])==0)
return i;
}
return -1;
}

int search_DEC(char opcode[]){
int i,j;
for(i=0;i<5;i++){
if(strcmp(opcode,DEC[i])==0)
return i;
}
return -1;
}

int calc_DEC(char opcode[],char operand[]){
int i=0,l,k=0;
char copy[10];
int j=0,m=0;
if(strcmp(opcode,"DC")==0){
switch(operand[0]){
case 'B':i=1;break;
case 'H':i=2;break;
case 'F':i=4;break;
case 'D':i=8;break;
}

for(j=2;operand[j]!='\'';j++){
op[m++]=operand[j];
}
op[m]='\0';
//printf(" %s ",op);

}

else{
l=strlen(operand);
switch(operand[l-1]){
case 'B':i=1;break;
case 'H':i=2;break;
case 'F':i=4;break;
case 'D':i=8;break;
}
for(j=0;j<=l-2;j++){
copy[k++]=operand[j];
}
copy[k]='\0';
//printf("%s",copy);
k=atoi(copy);
i=i*k;
}
return i;
}

void READ_LINE(){
char buff[20],word1[20],word2[20],word3[20];
int i,j=0,count=0;
label[0]=operand[0]=opcode[0]=word1[0]=word2[0]=word3[0]='\0';
for(i=0;line[i]!='\0';i++){
if(line[i]!=' '){
buff[j++]=line[i];
}
else{
buff[j]='\0';
strcpy(word3,word2);
strcpy(word2,word1);
strcpy(word1,buff);
j=0;
count++;
}
}
buff[j-1]='\0';
strcpy(word3,word2);
strcpy(word2,word1);
strcpy(word1,buff);
switch(count){
case 0: strcpy(opcode,word1);
    break;
case 1: strcpy(opcode,word2);
    strcpy(operand,word1);
    break;
case 2: strcpy(label,word3);
    strcpy(opcode,word2);
    strcpy(operand,word1);
    break;
}
}


void check_label(){
int k,dupsym=0;
for(k=0;k<symcount;k++){
if(strcmp(label,sym[k].symbol)==0){
sym[k].addr=-1;
dupsym=1;
break;
}
}
if(!dupsym){
strcpy(sym[symcount].symbol,label);
sym[symcount++].addr=lc;
}

//printf("%s %d",sym[symcount-1].symbol,sym[symcount-1].addr);
}


PASS1(){
FILE *input,*inter;
int p,m,d,l;
input=fopen("input.txt","r");
inter=fopen("inter.txt","w+");
if(input==NULL){
printf("Error");
exit(0);
}
if(inter==NULL){
printf("Error");
exit(0);
}

fgets(line,20,input);
READ_LINE();
printf("\nlabel:%s opcode:%s operand:%s",label,opcode,operand);

if(strcmp(opcode,"START")==0){
startaddr=atoi(operand);
lc=startaddr;
strcpy(prgname,label);
fprintf(inter,"%d",lc);
fgets(line,20,input);
}
else{
prgname[0]='\0';
startaddr=0;
lc=0;
fgets(line,20,input);
}


while(strcmp(line,"END\n")!=0){
READ_LINE();
printf("\nlabel:%s opcode:%s operand:%s",label,opcode,operand);
p=search_POT(opcode);
if(p!=-1){
l=0;
fprintf(inter,"\n%d",lc);
}
else{
d=search_DEC(opcode);
if(d!=-1){
l=calc_DEC(opcode,operand);
//if(label[0]!='\0')check_label();
if(strcmp(opcode,"DC")==0)fprintf(inter,"\n%d %s",lc,op);
else fprintf(inter,"\n%d --",lc);
//printf("%d",l);
}
else{
l=4;
fprintf(inter,"\n%d %s %s",lc,opcode,operand);
}

}
if(label[0]!='\0')check_label();
lc=lc+l;

fgets(line,20,input);
}
/*READ_LINE();
printf("\nopcode:%s",opcode);
*/
fprintf(inter,"\n%d",lc);
fclose(input);
fclose(inter);
}


char line1[20],lc1[5],op1[5],op2[5],opcode1[20];

void READ_LINE1(){
char buff[20],word1[20],word2[20],word3[20],word4[20];
int i,j=0,count=0;
lc1[0]=op1[0]=op2[0]=opcode1[0]=word1[0]=word2[0]=word3[0]=word4[0]='\0';
//printf("\n%s",line1);
for(i=0;line1[i]!='\0';i++){
if((line1[i]!=' ')&&(line1[i]!=',')){
buff[j++]=line1[i];
}
else{
buff[j]='\0';
strcpy(word4,word3);
strcpy(word3,word2);
strcpy(word2,word1);
strcpy(word1,buff);
j=0;
count++;
}
}
buff[j]='\0';
strcpy(word4,word3);
strcpy(word3,word2);
strcpy(word2,word1);
strcpy(word1,buff);
if(count==0){
strcpy(lc1,word1);
}
else if(count==1){
strcpy(lc1,word2);
strcpy(op1,word1);
}

else{
strcpy(lc1,word4);
strcpy(opcode1,word3);
strcpy(op1,word2);
strcpy(op2,word1);
}
//printf("lc=%s opcode=%s op1=%s op2=%s",lc1,opcode1,op1,op2);

}

int search_SYMTAB(){
int i,l,j,k=0;
char temp[5];
l=strlen(op2);
for(j=0;op2[j]!='\n';j++){
temp[k++]=op2[j];
}
//temp[k]='\0';

for(i=0;i<symcount;i++){
if(strcmp(temp,sym[i].symbol)==0){
return i;
}
}
return -1;
}

void PASS2(){
FILE *inter,*output;
int c;
inter=fopen("inter.txt","r");
output=fopen("output.txt","w+");

while(fgets(line1,20,inter)!=NULL){
//printf("%s",line1);
READ_LINE1();
if(op2[0]=='\0')
fprintf(output,"%s",line1);
else{
c=search_SYMTAB();
if(c==-1)printf("Undefined symbol");
else{
fprintf(output,"%s %s %s,%d\n",lc1,opcode1,op1,sym[c].addr);
}
}
}
}


void main(){
PASS1();
PASS2();
printf("\n");
}

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CODE OPTIMISATION

#include<stdio.h>
#include<string.h>
#include<ctype.h>

typedef struct{
    char arg1,arg2,op,result;
    char LHS,RHS[20];
}three_add;

three_add q[10];
int x=0,asc=65;
char OP[20],OD[20],t1,t2;//OP and OD represent operator and data stack
char substring[20];


char* substr(char* string,int start,int end){
    int k,l;
    memset(substring,0,sizeof(substring));
    substring[0]='\0';
    for(l=start,k=0;l<=end;l++,k++){
        substring[k]=string[l];
        substring[k+1]='\0';
    }
    return substring;
}

int priority(char ele){
int pr;
if(ele=='^')pr=3;
else if(ele=='*'||ele=='/'||ele=='%')pr=2;
else if(ele=='+'||ele=='-')pr=1;
else pr=0;
return pr;
}

void pop(char* op,char* od){
    char op1,od1,od2;
   
    op1=op[strlen(op)-1];//pop the operator at stack top from operator stack
    od2=od[strlen(od)-1];//topmost is stored in od2 not od1
    od1=od[strlen(od)-2];
   
    //Form the three address
    q[x].result=(char)asc;
    q[x].arg1=od1;
    q[x].op=op1;
    q[x].arg2=od2;
   
    //push the result into the data stack
    od[strlen(od)-2]=(char)asc;
    od[strlen(od)-1]='\0';
    op[strlen(op)-1]='\0';
   
    asc++;
    x++;
}
   

int main(){
    char string[20],str[20];
    int i=0,j,len1,len2;
    memset(str,0,sizeof(str));
    memset(string,0,sizeof(string));
    string[0]='\0';
    printf("Enter the infix expression:");
    scanf("%c=%s",&q[0].LHS,q[0].RHS);
    strcpy(string,q[0].RHS);   
    len1=strlen(string);
   
    for(i=0;i<strlen(string);i++){
        str[0]='\0';
       
        if(string[0]=='-'){
            q[x].arg1=string[1];/*if infix=-b+a+7+(b+c)-9-s*w then after this step, it is A+a+7+(b+c)-9-s*w where A=-b*/
            q[x].op='\0';
            q[x].arg2=string[0];//string[0] is arg2 and not arg1 because we are printing arg2 first
            q[x].result=(char)asc;
            str[0]=q[x].result;//write A to str
            str[1]='\0';
            strcat(str,substr(string,2,len1));//copy from + to -9
            asc++;
            x++;
            strcpy(string,str);
        }

        else if(string[i]=='('){
            memset(str,0,sizeof(str));
            q[x].arg1=string[i+1];//to replace (b+c) with B
            q[x].op=string[i+2];
            q[x].arg2=string[i+3];
            q[x].result=(char)asc;
            strcpy(str,substr(string,0,i-1));//copy from A+ to 7+ in str
            len2=strlen(str);
            str[len2]=q[x].result;//write B to str
            str[len2+1]='\0';           
            strcat(str,substr(string,i+5,len1));
            asc++;
            x++;
            strcpy(string,str);//hence the string in string is A+a+7+B-9-s*w
        }
    }
    for(i=0;i<strlen(string);i++){
        t1=string[i];//t1 is the current string
        if(priority(t1)==0){//it is data ie number and not operator
            OD[strlen(OD)]=t1;
        }
        else{
            for(j=(strlen(OP)-1);j>=0;j--){//traverse the stack
                t2=OP[j];//t2 is the stack top
                if(priority(t1)>priority(t2))
                break;
                else
                    pop(OP,OD);//pop until the priority of the symbol at stack top is less than the priority of the given symbol
                }
                OP[strlen(OP)]=t1;//push the current operator into the stack
            }
        }
            //the three addresses are formed in sequence
            for(i=strlen(OP)-1;i>=0;i--)//pop the remaining operators from the stack
                pop(OP,OD);
           
            if(q[0].LHS!=' '){//The last line of  three address For eg:S=c+a*b, A=a*b,B=c+A,S=B. It is for S=B line
                q[x].arg1=q[x-1].result;
                q[x].result=q[0].LHS;
            }
   
            //print the three address
           
            for(i=0;i<=x;i++){
                if(q[i].result!='\0'){
                    if(i==x)//last one
                    printf("\n\n%c:=%c",q[i].result,q[i].arg1);//done above
                    else
                    printf("\n\n%c:=%c %c %c",q[i].result,q[i].arg2,q[i].op,q[i].arg1);//arg2 printed first
                }
            }   
   
    return 0;
}

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SHIFT REDUCE PARSER

#include<stdio.h>
#include<stdlib.h>
//#include<conio.h>
#include<string.h>
char ip_sym[15],stack[15];
int ip_ptr=0,st_ptr=0,len,i;
char temp[2],temp2[2];
char act[15];
void check();
void main()
{
//clrscr();
printf("\n\t\t SHIFT REDUCE PARSER\n");
printf("\n GRAMMER\n");
printf("\n E->E+E\n E->E");
printf("\n E->E*E\n E->i");
printf("\n enter the input symbol:\t");
gets(ip_sym);
printf("\n\t stack implementation table");
printf("\n stack\t\t input symbol\t\t action");
printf("\n______\t\t ____________\t\t ______\n");
printf("\n $\t\t%s$\t\t\t--",ip_sym);
strcpy(act,"shift ");
temp[0]=ip_sym[ip_ptr];
temp[1]='\0';
strcat(act,temp);
len=strlen(ip_sym);
for(i=0;i<=len-1;i++)
{
stack[st_ptr]=ip_sym[ip_ptr];
stack[st_ptr+1]='\0';
ip_sym[ip_ptr]=' ';
ip_ptr++;
printf("\n $%s\t\t%s$\t\t\t%s",stack,ip_sym,act);
strcpy(act,"shift ");
temp[0]=ip_sym[ip_ptr];
temp[1]='\0';
strcat(act,temp);
check();
st_ptr++;
}
st_ptr++;
check();
}

void check()
{
int flag=0;
temp2[0]=stack[st_ptr];
temp2[1]='\0';
if((!strcmp(temp2,"i")))
{
 stack[st_ptr]='E';
printf("\n $%s\t\t%s$\t\t\tE->i",stack, ip_sym);
 flag=1; }
if((!strcmp(temp2,"+"))||(!strcmp(temp2,"*"))||(!strcmp(temp2,"/")))
{
 flag=1;
}
if((!strcmp(stack,"E+E"))||(!strcmp(stack,"E"))||(!strcmp(stack,"E*E")))
{
strcpy(stack,"E");
st_ptr=0;
if(!strcmp(stack,"E+E"))
printf("\n $%s\t\t%s$\t\t\tE->E+E",stack,ip_sym);
else
if(!strcmp(stack,"E"))
printf("\n $%s\t\t%s$\t\t\tE->E",stack,ip_sym);
else
printf("\n $%s\t\t%s$\t\t\tE->E*E",stack,ip_sym);
flag=1;
}

if(!strcmp(stack,"E")&&ip_ptr==len)
{
printf("\n $%s\t\t%s$\t\t\tACCEPT",stack,ip_sym);
//getch();
exit(0);
}
if(flag==0)
{
printf("\n  %s\t\t%s \t\t\tREJECT",stack,ip_sym);
//getch();
exit(0);
}
return;
}

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ELIMINATION OF LEFT RECURSION

#define SIZE 10
#include<stdio.h>
main () {
  char non_terminal;
  char beta,alpha;
  char production[SIZE];
  int index=3;            /* starting of the string following "->" */
  printf("Enter the grammar:\n");
  scanf("%s",production);
  non_terminal=production[0];
  if(non_terminal==production[index]) {
    alpha=production[index+1];
    printf("Grammar is left recursive.\n");
    while(production[index]!=0 && production[index]!='|')
      index++;
    if(production[index]!=0) {
      beta=production[index+1];
      printf("Grammar without left recursion:\n");
      printf("%c->%c%c\'",non_terminal,beta,non_terminal);
      printf("\n%c\'->%c%c\'|e\n",non_terminal,alpha,non_terminal);
    }
    else
      printf("Grammar can't be reduced\n");
  }
  else
    printf("Grammar is not left recursive.\n");
}

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FIRST AND FOLLOW

#include<stdio.h>
#include<ctype.h>
char a[100][8];

struct firTab
{
    int n;
    char firT[5];
};
struct folTab
{
    int n;
    char folT[5];
};
int n;
struct folTab follow[5];
struct firTab first[5];
int col;
void findFirst(char,char);
void findFollow(char,char);
void folTabOperation(char,char);
void firTabOperation(char,char);
void main()
{
    int i,j,c=0,cnt=0;
    char ip;
    char b[8];
    printf("Enter the number of productions(atmost 8):");
    scanf("%d",&n);
    printf("\nFIRST AND FOLLOW SET \n\nenter %d productions in format A->B+T\n",n);
    for(i=0;i<n;i++)
    {
    scanf("%s",&a[i]); 
    }
    for(i=0;i<n;i++)
    {   c=0;
    for(j=0;j<i+1;j++)
    {
        if(a[i][0] == b[j])
        {
            c=1;   
            break;
        }   
        }
    if(c !=1)
    {
      b[cnt] = a[i][0];
      cnt++;
    }              

    }
     printf("\n");

    for(i=0;i<cnt;i++)
    {   col=1;
    first[i].firT[0] = b[i];
    first[i].n=0;
    findFirst(b[i],i);
    }
    for(i=0;i<cnt;i++)
    {
    col=1;
    follow[i].folT[0] = b[i];
    follow[i].n=0;
    findFollow(b[i],i);
     }

    printf("\n");
   for(i=0;i<cnt;i++)
   {
    for(j=0;j<=first[i].n;j++)
    {
            if(j==0)
            {
                printf("First(%c) : {",first[i].firT[j]);
            }
            else
            {  
                printf(" %c",first[i].firT[j]);
            }
    }
    printf(" } ");
    printf("\n");
    }
     printf("\n");
   for(i=0;i<cnt;i++)
   {
    for(j=0;j<=follow[i].n;j++)
    {
            if(j==0)
            {
                printf("Follow(%c) : {",follow[i].folT[j]);
            }
            else
            {  
                printf(" %c",follow[i].folT[j]);
            }
    }
    printf(" } ");

    printf("\n");
    }

}
void findFirst(char ip,char pos)
{
    int i;
    for(i=0;i<n;i++)
    {
        if(ip == a[i][0])
        {
            if(isupper(a[i][3]))
            {
                findFirst(a[i][3],pos);
            }
            else
        {

        first[pos].firT[col]=a[i][3];
        first[pos].n++;
        col++;
            }
        }
    }
}
void findFollow(char ip,char row)
{   int i,j;
    if(row==0 && col==1)
    {
        follow[row].folT[col]= '$';
        col++;
        follow[row].n++;
    }
    for(i=0;i<n;i++)
    {
        for(j=3;j<7;j++)
        {
            if(a[i][j] == ip)
            {
                if(a[i][j+1] == '\0')
                {
                    if(a[i][j] != a[i][0])
                    {
                        folTabOperation(a[i][0],row);
                    }
                }
                else if(isupper(a[i][j+1]))
                {   if(a[i][j+1] != a[i][0])
                    {
                        firTabOperation(a[i][j+1],row);                                    

                }
                }
                else
                {
                    follow[row].folT[col] = a[i][j+1]; 
                    col++;
                    follow[row].n++;           


                }  
            }
        }
    }  
}
void folTabOperation(char ip,char row)
{   int i,j;
    for(i=0;i<5;i++)
    {
        if(ip == follow[i].folT[0])
        {
            for(j=1;j<=follow[i].n;j++)
            {
                follow[row].folT[col] = follow[i].folT[j];
                col++;
                follow[row].n++;
            }
        }
    }  
}
void firTabOperation(char ip,char row)
{  
        int i,j;
    for(i=0;i<5;i++)
    {
        if(ip == first[i].firT[0])
        {
            for(j=1;j<=first[i].n;j++)
            {
                if(first[i].firT[j] != '0')
                {
                    follow[row].folT[col] = first[i].firT[j];
                    follow[row].n++;
                    col++;                 
                }
                else
                {
                    folTabOperation(ip,row);
                }
            }
         }
    }

}

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