Design a lexical analyzer for given language and the lexical analyzer should ignore redundant spaces, tabs and new lines. It should also ignore comments. Although the syntax specification states that identifiers can be arbitrarily long, you may restrict the length to some reasonable value. Simulate the same in C language. GTU Complier Design (2170701)

#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"};

void main()

{

     char ch,str[25],seps[15]=" \t\n,;(){}[]#\"<>",oper[]="!%^&*-+=~|.<>/?"; int j;

     FILE *f1;

     f1 = fopen("input.txt","r");

     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 a literal\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;

}