<![CDATA[#include<stdio.h>
#include<ctype.h>
void FIRST(char[],char );
void result(char[],char);
int nop;
char prod[10][10];
void main()
{
int i;
char choice;
char c;
char res1[20];
clrscr();
printf("How many number of productions ? :");
scanf(" %d",&nop);
printf("enter the production string like E=E+T\n");
for(i=0;i<nop;i++)
{
printf("Enter productions Number %d : ",i+1);
scanf(" %s",prod[i]);
}
do
{
printf("\n Find the FIRST of :");
scanf(" %c",&c);
FIRST(res1,c);
printf("\n FIRST(%c)= { ",c);
for(i=0;res1[i]!='\0';i++)
printf(" %c ",res1[i]);
printf("}\n");
printf("press 'y' to continue : ");
scanf(" %c",&choice);
}
while(choice=='y'||choice =='Y');
}
void FIRST(char res[],char c)
{
int i,j,k;
char subres[5];
int eps;
subres[0]='\0';
res[0]='\0';
if(!(isupper(c)))
{
result(res,c);
return ;
}
for(i=0;i<nop;i++)
{
if(prod[i][0]==c)
{
if(prod[i][2]=='$')
result(res,'$');
else
{
j=2;
while(prod[i][j]!='\0')
{
eps=0;
FIRST(subres,prod[i][j]);
for(k=0;subres[k]!='\0';k++)
result(res,subres[k]);
for(k=0;subres[k]!='\0';k++)
if(subres[k]=='$')
{
eps=1;
break;
}
if(!eps)
break;
j++;
}
}
}
}
return ;
}
void result(char res[],char val)
{
int k;
for(k=0 ;res[k]!='\0';k++)
if(res[k]==val)
return;
res[k]=val;
res[k+1]='\0';
}]]>
